As an Amazon Associate, this site earns a commission from Amazon sales.











August 25th, 2022

Reloading Powder Grain Shapes — What You Need to Know

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

So how does powder grain shape affect pressure and muzzle velocity?
In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

Learn More with FREE Vihtavuori Reloading APP »

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

Permalink - Articles, Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
August 21st, 2022

Hand-Loading Basics Covered by Hodgdon Reloading Videos

Hodgdon Reloading Center Video

Hodgdon Reloading Center VideoHodgdon Powder Company (Hodgdon) offers a series of professionally-produced, “how-to” instructional videos through its online Reloading Data Center. These 3.5-minute videos present rifle, pistol, and shotshell reloading basics in an easy-to-understand, step-by-step format. These mobile-friendly, informative videos can also be viewed on a smart phone or tablet.

To watch the reloading videos go to the Reloading Data Center at hodgdon.com. With your cursor placed to the right/left of the displayed video, click to switch between pistol, rifle, and shotgun videos. Or, for your convenience, we have embedded the Rifle and Pistol videos here. Just click to watch!

Click to Watch Hodgdon Rifle Reloading Video:

Click to Watch Hodgdon Pistol Reloading Video:

In addition to these videos, Hodgdon’s Reloading Data Center (RDC) provides a wealth of information on Hodgdon®, IMR®, and Winchester® propellants. Along with reliable load data, you’ll find explanations of reloading basics, safety procedures, plus answers to frequently asked questions (FAQ).

Permalink - Videos, Reloading No Comments »
August 20th, 2022

Burn Rate Chart for Reloading Powders — Download HERE

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

Hey guys, you’ll probably want to download this Powder Burn Rate Chart issued by Hodgdon/IMR. This table includes the latest IMR powders including the Enduron series (IMR 4166, 4451, 4955, 7977), shown in green below. Please note, the chart is not limited to Hodgdon and IMR propellants. This table also includes popular powders from Accurate, Alliant, Norma, Ramshot (Western), Vihtavuori, and Winchester. There are a total of 163 powders listed in the chart.

This chart provides useful information for all hand-loaders. When doing load development, and testing one powder versus another, it’s generally wise to choose propellants that share the same relative burn rate, as least for starters. While this chart contains “Nov. 2019″ in the title, this is the most recent chart available from Hodgdon/IMR. It is the chart currently linked on the Hodgdon.com Reference Data Center.

NOTE: Hodgdon powders are shown in blue, IMR standard powders are shown in yellow, IMR Enduron powders are shown in green, and Winchester powder are shown in red. DOWNLOAD Chart HERE.


POWDER BURN RATE TABLE from Hodgdon/IMR

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

CLICK HERE to Download Chart as PDF File »

Burn Rate Chart from LoadData.com with 197 Powders

loaddata.com burn rate chart
The LoadData.com website has released its own burn rate chart, which is even more comprehensive than the official Hodgdon/IMR chart. We recommend starting with the Hodgdon/IMR listings, but if you can’t find a particular powder on the Hodgdon/IMR chart above, then consult the alternative from LoadData.com which lists 197 powders.

We also caution that, with any powder, start conservatively, at the low end of official load recommendations. Be aware that, even within the same burn range a ball powder can behave differently than an extruded powder. And some powders are much more temperature sensitive than others. Among the available powders on the market, some of best in terms of temp stability are the Alliant TS (temp stable) series, and the popular Hodgdon powders, such as H4350, made by ADI in Australia.


LoadData.com Relative Burn Rate Chart (197 Powders) »

Story find by EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
July 19th, 2022

Long-Term Powder Storage — What You Need to Know

Western Powders Blog SAAMI Storage

SUMMARY: Powder can have a very long shelf life. You need to watch for changes in smell and color. A reddish tinge, almost like rust on the powder, is a bad sign, as is a foul odor, not to be confused with a normal chemical smell. Either of these signs indicate it is time to dispose of your powder by means other than shooting.

Ever wondered about the stability of the propellants in your reloading room? There are some important things you should know about powder storage, to ensure consistent powder performance and safety. Western Powders (which has been acquired by Hodgdon) published an informative Q & A series entitled Dear Labby: Questions for our Ballistics Lab . Here are some excerpts that pertain to powder storage and shelf life. Worried that your powder may be too old? Western’s experts explain how to check your propellants for warning signs.

Proper Powder Storage

Q: I live in southern Arizona where it is very hot. I am told powders will become unstable if stored in an area not air-conditioned. My wife says no powder or primers in the house. Can powder be stored in a refrigerator? What about using a fireproof safe? I would appreciate your ideas. — M.C.

Lab Answer: SAAMI guidelines are pretty clear on issues of storage. They recommend storing smokeless powder in containers that will not allow pressure to build if the powder is ignited — ruling out gun safes and refrigerators.

CLICK HERE to Read SAAMI Guidelines for Powder Storage (PDF)

In their original containers, the lifespan of smokeless powders is quite long, even in hot, arid climates. In fact the lifespan is typically longer than the average handloader would need to store them. Stored safely in a garage or outbuilding, your powder should last years. If you see the powder developing a reddish tint, or giving off a foul odor, it is time to discard it.

Clumps in Powder Container

Q: I ordered some of your Accurate 1680 powder back about in December. I just now opened it … and it is full of clumps. My knowledge tells me that means moisture. Am I wrong? I just now broke the seal and it has been stored in a ammo can with desiccant packs around it and a dehumidifier running 14-16 hours a day. I can’t imagine this being my fault, if this does indicate moisture. I don’t know if the pink part on the label is suppose to be red or not, but it is definitely pink, so if it was red I am wondering if I was shipped an old container? I hope that this isn’t bad and I am stuck with it…

Lab Answer: All powder contains a certain amount of moisture. When the powder is stored or during shipping, it can go through temperature cycles. During the cycling, the moisture can be pulled to the surface and cause clumping. Clumping can also be caused by static electricity if too dry or the powder has limited graphite content. You can break up the clumps before metering and they shouldn’t be a problem. This will not affect the powder performance, so your product is fine. Accurate 1680 labels are designed in Pink. As a side note, specification for testing powder is at 70° F and 60% humidity.

Shelf Life and Packaging Dates

Q: Does powder ever get to old to use and what identifying marks does your company put on the canister for when it is made, You have helped me out a while ago when I asked about keeping my cowboy shooting under 950 fps and it works great less stress on the hand and the recoil is very minimum. — R.B.

Lab Answer: On one pound bottles, the number is on the corner in a silver box. If the powder was poured today, it would read 012815 followed by a lot number. The whole number would look something like 012815749. Eight pound bottles have a sticker on the bottom with an obvious date code. The lot number appears above the date.

Western Powders Blog SAAMI Storage

Permalink - Articles, Reloading, Tech Tip 3 Comments »
April 10th, 2022

TECH Tip: Powder Grain Shapes — What You Need to Know

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

So how does the shape affect pressure and muzzle velocity? In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

Learn More with FREE Vihtavuori Reloading APP »

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
February 20th, 2022

Sunday GunDay: .22 PPC for 300m Prone Competition

.22 PPC Rifle 300m prone

The 300 Meter .22 PPC — Smaller Caliber for Less Recoil

By GS Arizona
[This article originally appeared in Precision Shooting Magazine many years ago, but we are reprising it because the .22 PPC remains a notable cartridge for many disciplines, from benchrest to silhouette.]

I’ve spent the past few years pursuing the largely solitary pastime of 300 Meter shooting in the US. While it is a hugely popular sport in Europe, with thousands of competitors in each of various countries and overflowing national championships, in the U.S., 300 Meter shooting is simply a forgotten discipline. As an example, consider that the entry at the USA Shooting 300 Meter National Championships held at Fort Benning did not reach 20 competitors in [years past]. For those not familiar with the discipline, the 300 Meter ISSF target has a 100 mm ten ring, 200 mm 9 ring and so forth. That’s a 3.9″ ten ring at 328 yards for those of you who may object to the metric system, electricity and other intrusions upon a well settled universe (which ends at the dragons). [Editor’s Note: GS Arizona was a championship-class prone shooter, in both rimfire and centerfire disciplines, who had a popular online Blog, which has been closed.]

300 Meter Basics
300 Meter matches can be either three-position (prone, standing, kneeling) or all prone. Being of that age at which limbs aren’t limber and the mid-section obscures one’s view of the toes, I shoot prone matches only and leave the 3P to those for whom the term “shooting athlete” doesn’t produce an automatic smirk from the better half.

.22 PPC Rifle 300m prone

Like most 300 Meter shooters, I shoot a 6BR as my main rifle. As used in 300 Meter shooting, the 6BR is loaded with a 105-108gr bullet, with a velocity in the 2850 fps range. There is simply no cartridge out there at this time that delivers the accuracy, low recoil and ease of loading that can be had from the 6BR. That doesn’t mean we shouldn’t embark on a quixotic adventure now and then to find something better. This article is about one such search. So, if you don’t mind spending some time learning about an uphill struggle in a forgotten corner of the shooting world, pour a hot cup of coffee, get a plate of chocolate chip cookies and read on.

Getting Started–The Concept Behind the Project
The premise for building a .22 PPC was simple — less is more. Less recoil, that is, while retaining good ballistics and accuracy, should allow for higher scores. The hard part is meeting the ballistic and accuracy standards set by the 6BR. If pressed I might also admit to a desire to do something different. I made a decision early on in the project to stick to 80-grain bullets. I believe the 80 is pushing the envelope for safe and sane pressure in a case the size of the PPC; additionally, there are a number of manufacturers of 80-grain .224″ bullets so selection and testing can be more meaningful. Barrels are another consideration and all of the better barrel makers offer a 1:8″ twist .224 barrel (unlike the limited selection of 1:6.5″ twist required for 90 grain .224″ bullets).

With the basic parameters of a full-length .22 PPC case (reformed Lapua .220 Russian to be exact) and an 80-grain bullet established, a few other details needed attention. The first of these was specifying certain dimensions for the reamer maker. I chose not to change any of the essential dimensions of the .22 PPC such as headspace, shoulder angle or body taper, but there were a couple of areas that I felt needed to be different from the typical Benchrest PPC. These were neck diameter and throat length. With the outstanding quality of the Lapua brass, I elected to go with a 0.255″ neck diameter which would allow the use of unturned brass and still leave 0.002″ clearance around the neck of a loaded cartridge. The throat was specified longer than a standard PPC to allow for the length of the 80-grain bullets and avoid having the bullet go past the neck/shoulder junction.

300 Meter .22 PPC — Equipment List
Hardware
Action: RPA Quadlite, RPADefense.com.
Stock: Master Class Highpower Prone MasterClassStocks.com
Barrel: Broughton .224″ bore, 1:8″ twist, 30″ Palma contour
Rear Sight: Warner #1, Anschutz Iris, Warner-Tool.com
Front Sight: Gehmann Iris from Scott Riles
Trigger: Jewell 4 oz. one-stage
Bolt Knob: Keychain from 7-11 ($2.00)

Gunsmithing
Barrel fitting, sight, scope bases: Warner Tool Company.
Stock inletting, pillar bedding, and hardware: Alex Sitman,
Master Class Stocks.

Detours Along the Way
Like Quixote stumbling his way to his dreams, I’ve made a few mistakes. That 0.255″ neck diameter turned out to be the first. Turning brass isn’t a problem, but I was so captivated by the quality of the .220 Russian brass that I planned to skip turning or just take a light (0.001″) clean-up cut. Well, that’s fine, but as it turns out, PPC die makers assume you have turned necks and using unturned brass causes problems. The Redding Competition Seater, for instance, wanted to crimp the entire length of the neck onto the bullet. Turns out it was 0.250″ in the neck diameter of the sliding sleeve. This required reaming the sleeve which wasn’t too hard as the sleeve is made of relatively soft steel. Hand turning the chambering reamer with lots of care and oil took care of that problem. This opened up the neck to 0.255″ which might be 0.001″ more than ideal but I’ll live with it.

.22 PPC Rifle 300m proneSizing dies were another problem altogether. Forget using a non-bushing die with unturned brass–you’ll just overwork the neck to death. The Redding bushing dies worked well, though. Fired brass ends up at 0.254″ and is sized to 0.250″ in two steps (0.252″ and 0.250″) to maintain better concentricity.

I also got the throat length wrong as the base of the bullet (above the boat tail) is halfway up the neck and I want it just above the shoulder. I don’t know how I missed on that spec, but that’s what happened. As it turns out, the extra throat length hasn’t caused any problems with the Nosler 80, but it might with shorter or pointier bullets. Powder and primer choices became additional areas for demonstrating my inability to make good choices. You might think that adding a heavier bullet to an existing cartridge would be simple but it really turned into a full scale adventure.

Choice of Components and Smiths — Only the Best
Based on my previous favorable experience and that of a few friends, I ordered a Broughton barrel for the PPC, a .224″ bore 1:8″ twist, long enough to finish at 30 inches in what is generally referred to as a medium Palma taper. I haven’t been disappointed by the barrel: like all of those made by Tim North of Broughton Barrels, it is top notch. With the barrel and reamer in hand, they and the RPA Quadlite action were sent to Al Warner for barreling and then on to Alex Sitman for the stock. I can’t say enough good things about Alan’s metal work and Alex’s stock work. They have barreled and stocked many rifles for me over the years, all flawless. Alex’s Highpower Prone stock fits me like a comfortable moccasin. The trigger is a Jewell set at 4 oz., the rear sight is a Warner #1 and the front sight is a Scott Riles with a Centra aperture.

Eventually, the UPS man — purveyor of all things worth having — arrived with a long package and the real work began. Load testing and shooting can be a lot more frustrating than planning and talking to gunsmiths, but hopefully the eventual results make it worthwhile. I had a good supply of Nosler 80-grain bullets and some preconceived notions about powder and primers. Off to the loading bench.

Load Development + Accuracy Testing
Fire-forming the .220 Russian cases to the PPC chamber was a breeze: run an expander into the neck to get them to .224″, bump the shoulder 0.002″, load a caseful of IMR 4895 (about 23 grains) and insert a Nosler 77 (leftover from another project) and fire. I shot these at 100 yards while zeroing the rifle and was very impressed with the accuracy. Fouling was minimal, off to a promising start.

Once formed, I loaded the brass with Varget and the 80-grain bullets. Since Varget has given such good results in the 6BR, it was a natural starting point for this project. However, it quickly became evident that it might be too slow. While accuracy was excellent, powder fouling in the barrel was very heavy even at the highest charge tried (28.5 grains) and there was soot all the way down the shoulders of the cases. Cleaning the bore felt like patching a rusty water pipe after just 20 shots. I knew I’d never make it through a 60-shot match (about 70 shots with sighters) without cleaning[.]

Putting the .22 PPC to the Test in Competition
At this point, I took the PPC to a 300 Meter match with the Varget load. While it might not look perfect, I needed to try it. The first string was a 198 and I was able to clean the rifle immediately after firing. The second string was also a 198 but I had to fire the third string without cleaning. The effects of the fouling were evident in the last score, a 194.

While a 590 total isn’t bad for 300M, it was a bit below my average with the 6BR at this range – my home range that I knew well. More importantly, the score dropped as the group opened up in the third string when I wasn’t able to clean. At the Nationals all 60 shots are fired without a break for cleaning or additional sighters; therefore, Varget, while promising, wouldn’t work in the long run.

The next faster powder on my shelf was IMR 4895. I’d used it in the fire forming loads and if I had a lick of sense I would have tried it right away since the fire forming loads shot so well. However, stubbornly clinging to the preconceived notion that Varget was going to be a great powder for this combo cost me a month or so fooling with it. I then worked up loads with 4895 from 26.8 to 28.6 and saw that while 4895 was better suited to the case than Varget, it was still slow. The powder fouling was still occurring, though to a lesser degree. The shoulders still showed some soot, but less. I settled on 27.8 grains as a useful load and loaded 70 cases.

New Load for a New Home
At this point, I moved from Florida to Arizona causing a delay of several months in testing. The move also had an effect on the load as the hotter and drier climate in Arizona turned out to be much more suitable for 4895. Of course, I still had those 70 rounds loaded with 27.8 so I shot them in practice. Everything seemed OK but one primer (Federal 205M) pierced at the edge. I didn’t pay much attention to that as there were no other pressure signs and it was the first primer failure of any sort so far in this project. Extraction was fine, primer edges were nicely radiused and base growth was under two tenths. There was an opportunity to shoot a 500-yard prone match the following day so I reloaded the cases with the same load. At the match I pierced two more primers, this time right at the edge of the firing pin, causing two craters running into the firing pin hole. As you might imagine, all subsequent shots cratered into that area, although no more pierced.

I was contemplating a switch to Hodgdon Benchmark (slightly faster than H4895) until this point. Now, repairing the bolt face and switching to a tougher primer took priority. I loaded 25 rounds with CCI BR4 primers and 25 with Remington 7.5 primers. Both of these are well known for their tougher cups which I hoped would eliminate the piercing. I like the mild flash from the Federal 205 and believe it contributes to good accuracy, but I needed a primer that holds together more than I need to cut another tenth MOA. Bearing in mind that the powder charge itself might need reworking, I took those 50 rounds to the range to test them with the 27.8 gr. IMR 4895 load as it remains best to only change one thing at a time. Temperatures were in the 100 to 110 degree range during testing as they are for a good portion of the year here in Phoenix. If the load won’t work in hot temperatures, it just won’t work at all for me.

The primer testing at 200 yards showed the CCI BR4 primers to be better suited to this load than the Remington 7.5 primers. While no primer failed out of the 50 fired, the CCI BR4 primers gave distinctly better accuracy. I fired two ten-shot groups prone (scoped) with each, the Remington-primed groups averaged just over 1 MOA and the CCI-primed groups averaged 1/2 MOA. The difference between the two was principally in the amount of elevation in the groups. Given that result, as well as previous good experience with the CCI primers in the 6BR, I settled on the CCI BR4 primers for the PPC.

Final Testing at 500 Yards–It all Comes Together
While the purpose of the 80-grain PPC is 300 Meter shooting, those matches are somewhat hard to find so I’ve done most of my testing at 200 yards on the local public range (Ben Avery Shooting Facility in Phoenix) and at 500 yards in some of the local prone matches. With the primer issue potentially resolved, I went back to the 500-yard range to make sure the load held good elevation at that distance.

Final testing at 500 yards was a complete success. I fired one group of 24 shots from the prone position. Elevation for the bulk of the group was right at 3″ (0.6 MOA), the horizontal spread was somewhat larger as the group was fired in gusty, fast-switching conditions. The CCI BR4 primers functioned flawlessly, with no sign of pressure despite ambient temperatures over 100° F. None of this should be taken as a general statement of inadequacy of Federal primers. I have used (and continue to use) the very same lot of Federal 205M primers in my 6BR and have not experienced any problems at all. Simply stated, the 80-grain .22 PPC is an odd duck and has special requirements when fired under the conditions that prevail in my area.

At this point, I’ve determined that the basic premise of a .22 PPC for 300 Meter matches is perfectly viable, even if it is quite a bit more complex an undertaking than the 6BR. Recoil reduction over the 6BR was minimal, bordering on unnoticeable, but accuracy is on a par with the 6BR, perhaps slightly better. As a nice bonus, the PPC has proven to be quite useful for the 500-yard prone matches that are a regular part of the Phoenix shooting scene and it never fails to spark a good conversation with a new friend when I’m practicing or testing at the range. Future plans include testing Berger and Hornady 75 and 80-grain bullets and Hodgdon Benchmark powder. And, after conferring with your moderator, who ran some simulations in QuickLOAD, I’ll be trying Reloder 15 soon (QuickLOAD predicts RL15 allows 100% load density with good velocity). At some point I’ll also have the reamer reground for a shorter throat and tighter neck, but probably not until time comes to rebarrel.

6mmBR Norma versus .22 PPC

For the shooter who wants a superbly accurate, easy to load cartridge for 300 Meters to 600 yards, you simply can’t beat the 6BR. Everything you need, including brass, dies, reamers and knowledge are just a phone call away. The .22 PPC, by contrast, is an uphill struggle. The chambering reamer was custom ground to my specifications to allow unturned brass, as well as a longer freebore for the 75- and 80-grain bullets that are the heart of the project. The no-turn necks also meant that the Redding Competition Seater (an excellent unit) had to be reworked to allow for the thicker neck diameter. Once those hurdles were overcome I struggled to find the best powder for this combination–and I’m still searching. Unlike the 6BR where any of a half dozen or more powders will do the job (Varget, Reloder 15, N140, N540, IMR 4895, Norma 203B, etc.) the .22 PPC with heavy bullets has proven finicky with even the most accurate powders leaving fairly heavy carbon fouling.

Despite the problems, the .22 PPC offers a bit more pure accuracy than the 6BR and also a tiny bit less recoil. Both of these things can contribute to slightly higher scores in prone matches. However, to get the most out of the PPC, one must find the time to clean between 20 shot strings–a not inconsiderable effort sometimes in the mad rush of pit changes, scoring, shooting and just plain being tired.

This rifle was initially a .223 and when that cartridge proved unsatisfactory for my purposes, I had it rebuilt as the .22 PPC you see here. I like it and I enjoy the challenge, but I would not recommend this combination as someone’s primary rifle; it can get a bit frustrating. To put it into another context, the 6BR is like a 350 Chevy, it’ll just keep on doing the job forever, no matter what. The .22 PPC is like a Ferrari, it’ll scream when you do everything right, but it takes more attention to detail and a lot more maintenance. You wouldn’t want a Ferrari as your only car and likewise, you would be better off making the .22 PPC a second rifle.

Parting Shots — The .22 PPC vs. 6mm BR
If you’re looking for a simple, accurate and reliable cartridge for 200 to 600 yards, you probably can’t improve on the 6BR. However, if you’re someone who finds the journey as rewarding as reaching the destination, then you may very well enjoy a .22 PPC for prone shooting. While I received a great deal of help in this project from friends, gunsmiths, suppliers and parts makers far and wide, I really must acknowledge the huge debt we all owe to Ferris Pindell and Dr. Lou Palmisano. Without them there would be no PPC. We truly stand on the shoulders of giants.

Copyright © Precision Shooting Magazine and GS Arizona. Reprinted by permission.
Permalink - Articles, Bullets, Brass, Ammo, Competition, Reloading 2 Comments »
January 12th, 2022

Powder Burn Rate Comparison Table — Download HERE

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

Hey guys, you’ll probably want to download this Powder Burn Rate Chart issued by Hodgdon/IMR. This table includes the latest IMR powders including the Enduron series (IMR 4166, 4451, 4955, 7977), shown in green below. Please note, the chart is not limited to Hodgdon and IMR propellants. This table also includes popular powders from Accurate, Alliant, Norma, Ramshot (Western), Vihtavuori, and Winchester. There are a total of 163 powders listed in the chart.

This chart provides useful information for all hand-loaders. When doing load development, and testing one powder versus another, it’s generally wise to choose propellants that share the same relative burn rate, as least for starters. While this chart contains “Nov. 2019″ in the title, this is the most recent chart available from Hodgdon/IMR. It is the chart currently linked on the Hodgdon.com Reference Data Center.

NOTE: Hodgdon powders are shown in blue, IMR standard powders are shown in yellow, IMR Enduron powders are shown in green, and Winchester powder are shown in red. DOWNLOAD Chart HERE.


POWDER BURN RATE TABLE from Hodgdon/IMR

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

CLICK HERE to Download Chart as PDF File »

Burn Rate Chart from LoadData.com with 197 Powders

loaddata.com burn rate chart
The LoadData.com website has released its own burn rate chart, which is even more comprehensive than the official Hodgdon/IMR chart. We recommend starting with the Hodgdon/IMR listings, but if you can’t find a particular powder on the Hodgdon/IMR chart above, then consult the alternative from LoadData.com which lists 197 powders.

We also caution that, with any powder, start conservatively, at the low end of official load recommendations. Be aware that, even within the same burn range a ball powder can behave differently than an extruded powder. And some powders are much more temperature sensitive than others. Among the available powders on the market, some of best in terms of temp stability are the Alliant TS (temp stable) series, and the popular Hodgdon powders, such as H4350, made by ADI in Australia.


LoadData.com Relative Burn Rate Chart (197 Powders) »

Story find by EdLongrange. We welcome reader submissions.
Permalink - Articles, Reloading, Tech Tip 2 Comments »
September 28th, 2021

Hodgdon Closes GOEX Black Powder Production Plant in Louisiana

Hodgdon Powder Goex black powder camp minden closure

Hodgdon Powder Company, on 9/27/2021, announced that it would be shutting down the GOEX Black Powder production center at Camp Minden in Louisiana. This was the last remaining black powder factory in the United States. This could mean “hard times ahead for traditional muzzle-loading and BPCR shooting” (source: NAMLhunt.com). Here is the official announcement on the Hodgdon website:

“Effective immediately, Hodgdon Powder Company, Inc. has made the decision to cease manufacturing operations at the company’s Camp Minden, Louisiana site while evaluating strategic options for the black powder business.

The business will wind down operations while an evaluation process on the future of the black powder business takes place. Strategic options for the GOEX and Olde Eynsford brands of black powder, along with the manufacturing capabilities, will include a potential sale of the business. All affected employees will be retained through December 31, 2021 to assist in an orderly closing of the site and receive severance commensurate with their years of service to the company.

The Hodgdon Powder Co., Inc has been honored to have been a part of the GOEX Powder legacy and sustains a fond appreciation for sporting customers who have enjoyed shooting GOEX powders.”

Hodgdon Powder Goex black powder camp minden closure

Ironically, the GOEX logo states “The Tradition Continues”.
With this announcement, GOEX might be gone for good.

Here is a related report by the NRA’s American Rifleman:

The closure eliminates the only domestic source of blackpowder in the United States. According to a company press release, Hodgdon will evaluate “strategic options for the black powder business”, including a potential sale of the company.

GOEX Powder has a long, storied history that starts in 1802 with the building of a blackpowder plant on the Brandywine River in Delaware by E.I. Du Pont de Nemours. Production expanded with the building of the Belin plant in Moosic, Penn., in 1912, and the facility supplied military blackpowder during both world wars, as well as the Korean and Vietnam wars. In the 1970s, the Belin plant was incorporated into the GOEX family, and production moved to Minden, LA, in 1997. [In 1969] GOEX was purchased by Hodgdon Powder Company [which] spent years updating equipment at the Minden facility, enhancing employee safety and blackpowder quality.

Despite Hodgdon’s efforts, the GOEX facility at Camp Minden has a history of manufacturing incidents stretching back to 1998, including a June 2011 incident where 1,000 pounds of blackpowder exploded. The latest incident at GOEX occurred on June 18, 2021, when an explosion required the evacuation of 15 employees inside the facility. Nobody was injured, but the plant observed a 24- to 48-hour waiting period to ensure that nothing else at the facility ignited.

Permalink Bullets, Brass, Ammo, Hunting/Varminting, News No Comments »
August 24th, 2021

What You Need to Know about Powder Grain Shapes

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

So how does powder grain shape affect pressure and muzzle velocity?
In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

Learn More with FREE Vihtavuori Reloading APP »

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

Permalink Bullets, Brass, Ammo, Reloading No Comments »
April 1st, 2021

Can’t Find Reloading Powder? 1000 Grain Bottles Coming Soon!

DOT small powder bottles

We all know reloading powder is in VERY short supply these days. And the most popular propellants, such as Varget, H4350, and Reloder 16, are almost impossible to find at reasonable prices. Thankfully, there is a new solution in the works — smaller containers. This should give handloaders a whole new way to source those precious powders needed for a day at the range. And even if the volume is limited, something is ALWAYS better than nothing, right?

The big (and small) news for reloaders is that the major powder suppliers plan to start shipping powders in more compact, easy-to-ship containers. Instead of buying a pound of powder, you will be able to purchase an efficient, handy 1000 grain container. These are light weight (just 1/7th of a pound) so they are convenient to transport and carry. And you’ll never have the problem of over supply. A 1000-grain container with load approximately 33 6mm BR rounds — that should be plenty for a day at the range. We’re blessed to have this new compact powder option thanks to the U.S. Department of Transportation (DOT).

DOT small powder bottlesThe U.S. Department of Transportation (DOT) recently approved new smaller containers for shipment of smokeless powder. The new containers are designed to hold 1000 grains, exactly one-seventh of a pound. That works out to 2.29 ounces of powder — quite a bit less than you are getting currently with one-pound (16 oz.) containers.

Here how it works out:
7000 grains = 1 pound = 16 ounces
1000 grains = 0.143 pounds = 2.29 ounces

Many products — from cereal boxes to Snickers bars — have been down-sized in recent years. Now downsizing has come to the powder marketplace. The strategy behind the smaller containers is simple. In a market where demand vastly outstrips available supply, the smaller containers allow powder-makers to generate more revenue with a given amount of powder inventory. Will consumers accept the smaller powder containers? Probably so — 1000 grains is enough to load 20-22 rounds of .308 Winchester. In the current marketplace (with many powders virtually impossible to find), most consumers would probably prefer to get 2.3 ounces of their favorite powder, rather than nothing at all. (NOTE: The major powder suppliers will continue to offer popular powders in 1-lb, and 8-lb containers. The new 1000-grain containers will be phased-in over time, as an alternative to the larger containers).

Why the small bottles? One industry spokesman (who asked not to be named) explained: “We’ve had a severe shortage of smokeless powder for nearly two years. The powder production plants are running at full capacity, but there’s only so much finished product to go around. By moving to smaller containers, we can ensure that our customers at least get some powder, even if it’s not as much as they want.”

Why are the new containers 2.3 ounces rather than 8 ounces (half a pound) or 4 ounces (one-quarter pound)? One of the engineers who helped develop the new DOT-approved container explained: “We looked at various sizes. We knew we had to reduce the volume significantly to achieve our unit quantity sales goals. Some of our marketing guys liked the four-ounce option — the ‘Quarter-Pounder’. That had a nice ring to it, but ultimately we decided on the 1000 grain capacity. To the average consumer, one thousand grains sounds like a large amount of powder, even if it’s really only 2.3 ounces. This size also made it much easier to bundle the powder in six-packs. We think the six-packs will be a big hit. You get nearly a pound of powder, but you can mix and match with a variety of different propellants.”

Less Bang for Your Buck?
We’re told the new 2.3-ounce powder bottles will retail for around $11.99, i.e. about $5.21 per ounce. At that price, it may seem like you’re getting less bang for your buck … but hey, something is better than nothing, right?

DOT small powder bottlesCurrently, when you can find them, quality reloading powders are going for $45-$60 per pound (in 1-lb containers). At $45 per pound, you’re paying $2.81 per ounce. That means that the new mini-containers will be roughly twice as expensive as current one-pounders ($5.21 per ounce vs. $2.81 per ounce).

Along with the 2.3-ounce containers, the DOT has approved “six-pack” consolidated delivery units that will hold six, 1000-grain containers. Some manufacturers plan to offer “variety packs” with a selection of various powders in the 1000-grain bottles. Wouldn’t it be cool to have a six-pack with H322, H4895, Varget, H4350, H4831sc, and Retumbo?

Permalink Bullets, Brass, Ammo, New Product, News, Reloading, Tech Tip 8 Comments »
September 27th, 2020

Sunday GunDay: Shelley Davidson’s Amazing “Tinker Toy” 30 BR

Shelly Davidson Tinker Toy 30 BR

Editor’s NOTE: Shelley Davidson passed away in 2008 after a courageous battle with cancer. He was one of the great innovators in benchrest rifle design. This article, written before Shelley died, showcases Shelley’s creative talents at their best. His “Tinker Toy” design will always be a tribute to Shelley’s fabricating skills and imagination.


Shelley Davidson — a brilliant innovator. R.I.P. Shelley — you will not be forgotten.

Shelley Davidson’s peers called his radical rifle the “Tinker Toy” gun. We call it revolutionary. Even now, 14 years after its creation, there’s nothing quite like it. This innovative, skeleton design threw conventional wisdom to the winds. Shelley readily concedes he “broke the rules” of benchrest rifle building. But this was inspired rule-breaking, because Davidson’s rifle shot like a house on fire. The Tinker Toy gun won its first matches, both for Score AND for Group. And this rifle also delivered many “zero groups” in Gene Begg’s Texas Tunnel. Hats off to Shelley for conceiving and building a truly radical rifle that was also wicked accurate and successful in competition.

tinker toy davidson 20 BR benchrest rifle

Tinker Toy 30 BR — Radical As It Gets

Report by Shelley Davidson
Although I’m not big on naming rifles, my shooting buddies have christened the gun “Tinker Toy.” I can live with that as it does kind of look as if it was made with a Tinker Toy set.

Origins of the Project
This project began with some wild ideas I had in the fall of 2006 about using magnets to tune a barrel. My idea was to use one magnet on the barrel and another on the stock so they pushed against each other to counter gravity-induced barrel sag (and possibly) tame barrel vibration in a beneficial manner. The only way to test these ideas was to build the device and mount it on a gun. That meant I had to build a new rifle because there was no place to mount a magnet on the stock of a conventional benchrest rig. I had a Kelbly-stocked heavy varmint stock with a Michael Kavanaugh paint job on it. I didn’t think Kav would ever forgive me if I started drilling holes in one of his works of art. My light varmint was in a carbon fiber Scoville stock that costs about a grand. Drilling into the Scoville for an experiment just smacked of bad judgment. So, the magnet thing was my first motivation for designing a new stock. As long as I was building from scratch I decided to offset the barrel and action 0.75″ to the right to counteract the spin/torque from the bullet.

Although there’s nothing new here, my second motivation was to build a 30BR that could shoot in the 10.5 lb light varmint class in NBRSA. The magnetic tuner will automatically make this gun illegal in the IBS. The IBS has declared all barrel attachments un-safe and have outlawed them. I personally feel that the IBS really outlawed all barrel attachments to prevent experimentation and innovation. But at least we have NBRSA matches.

Designing the New Gun — Thinking “Outside the Box”
Once I’d decided to build a lightweight stock that could support experimental devices out near the muzzle, I started drawing up some rough plans. I also took a trip to Jerry Stiller’s shop in Wylie, Texas for a brainstorming session with Jerry, the maker of Viper and other Benchrest actions. Jerry is a school-trained mechanical engineer and thinks differently than I do. I came away from Stiller’s shop with my design roughed out and sketched on paper. The design violated several covenants of conventional wisdom for building competition BR rifles. For instance, two-piece stocks stress the action. Stress reduction is why most BR rifles are glued into the stock. Another myth is that metal stocks vibrate too much so wood or foam-filled fiberglass or carbon fiber are used.

Tinker Toy Rifle DESIGN FEATURES

Shelly Davidson’s Rifle was so innovative, that almost every feature, except the bare action, is very different than you’ll find on most Benchrest rigs. Accordingly we felt it would be useful to isolate and describe the key design features, from stem to stern. Click thumbnails to view FULL-SIZE PHOTOS.

Front Bracket with Magnetic Tuner
The tuner consists of one rare earth magnet attached to the stock and another attached to a barrel sleeve with the magnets oriented so as to make the magnetic force repel each other. The purpose is to counter “barrel droop” and, hopefully, dampen barrel vibration. The lower magnet is carried on a threaded shaft (with lock ring), allowing the magnet to be raised up and down to adjust the “up push” on the barrel.

Tubular Fore-Arm Supported by Brackets
Three brackets support two tubes, one on either side of the barrel. The rear-most bracket is sandwiched between the barrel and the action. Four inches forward (max distance allowed for barrel blocks) a second bracket grips the barrel. Near the muzzle a third bracket secures the ends of the tubes and holds the magnetic tuner. To allow barrel offset, the left tube is 1″ diameter tube while the right tube is 5/8″ diameter.

Offset Barrel
The rifle rests on a 3″ wide plate attached to the underside of the two fore-end tubes. With the plate centered in the front sandbag, the barreled action is actually offset 0.75″ to the right (looking forward from the breech). The purpose of this offset is to keep more weight on the right side to counter the tendency of the rifle to torque counter-clockwise. Two different diameter tubes allow for the built-in offset.

Floating Action without Sub-Support or Bedding
On the Tinker Toy gun, the action serves as a load-bearing assembly, holding the barrel in the front, and the skeleton buttstock (or “keel”) in the rear. Shelley was told that accuracy would suffer if you stressed a benchrest action in this manner but that proved untrue. It is a very simple solution to building a rifle, and it eliminates the need to bed the action. The forearm attaches to the action via a bracket installed like a recoil lug.

Skeleton Rear “Keel” Affixed Directly to Action
Davidson’s Tinker Toy does not have a conventional rear buttstock. Instead there is low-profile, v-shaped metal “keel”, as Davidson calls it, that rides the rear bag. The keel is supported by a tubular backbone that attaches at the rear of the Diamondback action. At the butt end is an aluminum plate covered with bubble wrap that serves as a butt pad. The skeletonized rear section helps the rifle maintain a very low center of gravity.

Locked Scope with External Windage and Elevation Adjustment
Shelley ran an older Leupold 36X Benchrest Scope with front-adjusting objective. To eliminate slop or loose tolerances in the erector mechanism that could cause changes in point of impact, the internals have been locked up by Jackie Schmidt. To move the cross-hairs relative to the bore axis, Shelley has a special Jewell/Foster rear ring that allows a limited amount of lateral and vertical movement of the entire scope body.

TINKER TOY SPECIFICATIONS

Action: Stiller SS Diamondback Drop-Port (1/2″ short), with .308 Bolt Face.
Barrel: Shilen .308 caliber, 17-twist, HV.
Chambering: 30BR, .330″ neck, Pacific Tool & Gauge Robinett Reamer.
Stock: Davidson Custom Tubular Stock with 0.75″ Offset Barreled Action.
Tube Construction: 6061 Aluminum, 1″ diameter (left), 5/8″ diameter (right).
Load: H4198 powder and 118gr Ronnie Cheek bullets. Loaded to 2980 fps.
Trigger: Jewell, 2 ounce BR.
Tuner: Custom, Adjustable with Opposing Magnets.
Optics: Leupold 36X (locked by J. Schmidt).
Rings: Jewell Foster External Adjusting Rings.

Stiller Diamondback Action and Shilen 17-Twist Barrel
I had wanted to use an aluminum Stiller Cobra drop port with a 6mmBR bolt face but Jerry had none in stock and he estimated it would be a year before one was available. Although I’ve waited for up to a year for an action in the past, I wanted to build this rifle during the fall of 2006 while the weather was pleasant enough to work in my unheated and un-air-conditioned garage shop. Jerry did have a 1/2″ short stainless steel Diamondback in stock so I purchased it even though it would add 3 ounces to the gun compared to the aluminum Cobra. Three ounces is a lot of weight when you’re working with a 10.5-lb limit. I had a heavy varmint contour Shilen 17-twist barrel that would work nicely and I had a Jewell trigger on a rifle that I wasn’t using at the time. I also decided to use my Leupold 36X (locked-up by Jackie Schmidt) with the Jewell/Foster adjustable rings.

Building the Tube Fore-Arm and Brackets
I took a wild guess as to tubing thickness and settled on .035″ for the 1″ left fore-arm tube and .058″ for the 5/8″ right fore-arm tube. All of the flat stock and tubes are 6061 Aluminum. I did the lathe work and the mill work and every evening I’d put the parts together and think about the proper way to proceed.

tube benchrest rifle

When the parts were mostly made, I started thinking that this was a truly ugly rifle. I thought about painting it but that wasn’t a good option as many of the parts are designed to slide over others and glue together. Anodizing was the best answer so while looking on the Internet for local anodizing shops I Googled “Home Anodizing”. Sure enough there were a few sites that told about how to anodize at home. I picked up some battery acid from NAPA Auto Supply, some Rit Clothes Dye from Wal-Mart, and a bunch of distilled water from the grocery store. Using an old battery charger as my dc power supply I started anodizing and dying the eighteen parts that went into the stock. Although I had to strip and re-anodize some of the parts, the work turned out acceptable.

Putting it All Together–Lug-Mounting the Fore-Arm and Lots of Epoxy
The barrel contour had to be modified to work with the stock which attaches by way of a rear plate which mounts like a recoil lug and a plate that ties the barrel and the stock tubes together 4″ forward of the bolt face. The four-inch maximum distance is a NBRSA rule concerning barrel blocks.

Davidson Benchrest 30BR

Davidson 30BR group targetThe recoil lug-style stock mount is probably the only truly innovative thing I did other than the opposing-magnet tuner. Basically, the rear bracket is sandwiched between the receiver face and the barrel shoulder–positioned where a conventional recoil lug would go. I also added a brass ring (visible in photo) between the anodized bracket and the barrel. This was done to distribute loads over a wider surface area. (I was concerned that the bracket material was fairly soft and I didn’t want to crush it as I torqued the barrel in place.) After fitting the barrel and plates I glued the entire gun together using epoxy and various LocTite adhesives. The rest of the parts were assembled but I did not Loctite the scope bases since I thought I’d be disassembling the rifle for re-work after the first trials. That came back to bite me during later testing when the gun started shooting erratically and I went down a couple of blind alleys before finding the loose bases.

Range Testing–Results Are Very Positive
The first range session was a real shocker. Even though the wind was up to 10mph and twitchy, the rifle showed promise from the very first shot. I really didn’t expect that kind of performance without, at least, some rework. After sighting in, I shot five, 5-shot groups that, when averaged together, measured .223″. That’s good enough to win some benchrest group matches. But I wasn’t finished with the gun yet–I still wanted to try out my magnetic tuner concept.

Magnetic Benchrest Tuner Davidson

The Magnetic Tuner
Next, I built the magnetic tuner. The tuner consists of one rare earth magnet attached to the stock and another attached to a barrel sleeve with the magnets oriented so the magnetic forces repel each other. In order to test the magnets and to determine if the rifle really shot as well as it seemed to, I took it to Gene Beggs’s shooting tunnel in Odessa, Texas. I spent two days at the tunnel testing loads and then installed the magnetic tuner. The gun shoots well with the magnets and shoots well without them. I suppose I can’t make any claims as to how much, if any, improvement the magnets make. Gene said that my gun was the most accurate rifle to be tested at his one-year-old shooting facility: “Shelley Davidson brought one of the most unusual rifles I had ever seen; he called it his ‘Tube Gun.’ And boy, did it ever shoot! It still holds the record in the tunnel as the rifle that shot more zeros than any other to date.” I definitely recommend Gene’s facility for testing and refining shooting techniques and loads.

Competition — Tinker Toy Won Both Score and Group Matches

Finally the big day arrived when I’d shoot the first match with my new gun. The North Texas Shooters Association was holding its first club match of the 2007 season. At the Denton, Texas matches we shoot a Score Match in the morning and a Group Match in the afternoon. The March event was at 100 yards and the April match will be at 200 yards and so on alternating throughout the benchrest season.

Davidson tube BR rifle Score MatchMatch One–Tinker Toy Wins Score with a 250 – 17X
Since the gun is chambered in 30BR and that chambering is almost immune to tuning woes, I preloaded 130 rounds with H4198 powder and 118gr Cheek bullets. I used my SEB front rest and rear bag which are made by Sebastian Lambang in Indonesia. Everything came together, and Tinker Toy demonstrated that the accuracy it showed in the tunnel was no fluke. The gun shot great and I won the morning match with a 250, 17X. The day was quite windy and the next best shooter scored a 250, 15X. So I’d chalked up my first win.

Match Two–Tinker Toy Wins Group with a .2282″ Agg
Tinker Toy won the afternoon group match I entered with a five-group Aggregate of .2282″. (The second place score was .2568″.) My groups were .149″, .197″, .243″, .302″ (oops), and .250″. You know how some folks say a 30BR can’t be competitive with a PPC? Well that .2282″ Agg won’t break any records, but it is good enough to win some regional registered BR matches. So this rifle has demonstrated an ability to win in both Score and Group matches. Obviously I have a very good Shilen barrel, great Cheek bullets and the rest of the components are doing their jobs as well. But, the stock is also working well.

Score Shooting vs. Group Shooting–The Rules
In a score match, the shooter shoots one bullet at each of five record targets, which are clustered on one target sheet. The Aggregate score of five of these targets determines the winner. If the shooter touches the 10 ring on all of his 25 targets he can score a “clean” 250 score. Usually there will be more than one shooter who scores a 250 so the winner is determined by the X-count. The 1/2″ 10-point ring has a 1/16″ dot in its center. Touching the X dot adds to the shooters X count. In short-range group matches, the shooter must try to put five bullets through the same hole. At each distance (100 or 200), five, 5-shot matches are scored, the group sizes are added together (MOA equivalent at 200) and the total is divided by five to arrive at an Aggregate score.

Permalink - Articles, Competition, Gear Review, Gunsmithing 1 Comment »
June 9th, 2020

Powder Burn Rate Comparison Table — Download HERE

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

Day after day, one of AccurateShooter’s most-visited web pages is a reference guide featuring a comparative burn rate chart, ranking powders from fastest to slowest. Compiled by Hodgdon Powder Co., this Burn Rate Chart displays the relative burn rates of 163 different powders. Here is the latest table, released by Hodgdon in November of 2019.

You’ll want to download this Powder Burn Rate Table. This table shows the latest IMR powders including the Enduron series (IMR 4166, 4451, 4955, 7977), highlighted in green. This 163-entry comparison table provides vital information for hand-loaders. Note — this invaluable chart is not limited to Hodgdon and IMR propellants. This burn rate chart ranks powders from eight major powder-makers: Accurate, Alliant, Hodgdon, IMR, Norma, Ramshot (Western), Vihtavuori, and Winchester.

This chart provides useful information for all hand-loaders. When doing load development, and testing one powder versus another, it’s generally wise to choose propellants that share the same relative burn rate, as least for starters.

NOTE: Hodgdon powders are blue, IMR Enduron powders are green, IMR standard powders are yellow, and Winchester powders are red. DOWNLOAD Chart HERE.


Latest POWDER BURN RATE TABLE from HODGDON/IMR

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

CLICK HERE to Download Chart as PDF File

Story find by EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 4 Comments »
April 28th, 2020

Vihtavuori Explains Powder Grain Shapes

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

So how does the shape affect pressure and muzzle velocity? In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

Learn More with FREE Vihtavuori Reloading APP »

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 1 Comment »
April 18th, 2020

Comparative Burn-Rate Chart Lists 163 Powders

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

Day after day, one of AccurateShooter’s most-visited web pages is a reference guide featuring a comparative burn rate chart, ranking powders from fastest to slowest. Compiled by Hodgdon Powder Co., this Burn Rate Chart displays the relative burn rates of 163 different powders. Here is the latest table, released by Hodgdon in November of 2019.

You’ll want to download this Powder Burn Rate Table. This table shows the latest IMR powders including the Enduron series (IMR 4166, 4451, 4955, 7977), highlighted in green. This 163-entry comparison table provides vital information for hand-loaders. Note — this invaluable chart is not limited to Hodgdon and IMR propellants. This burn rate chart ranks powders from eight major powder-makers: Accurate, Alliant, Hodgdon, IMR, Norma, Ramshot (Western), Vihtavuori, and Winchester.

This chart provides useful information for all hand-loaders. When doing load development, and testing one powder versus another, it’s generally wise to choose propellants that share the same relative burn rate, as least for starters.

NOTE: Hodgdon powders are blue, IMR Enduron powders are green, IMR standard powders are yellow, and Winchester powders are red. DOWNLOAD Chart HERE.


Latest POWDER BURN RATE TABLE from HODGDON/IMR

Hodgdon IMR Winchester Burn Rate Powder speed table relative table chart

CLICK HERE to Download Chart as PDF File

Story find by EdLongrange. We welcome reader submissions.
Permalink - Articles, Bullets, Brass, Ammo, Reloading 4 Comments »
January 23rd, 2019

Access Hodgdon and IMR Load Data in Reload Data Center

Hodgdon Reloading data Center hand loading powder

Hodgdon Reloading data Center hand loading powder

Hodgdon and IMR powders, including H4198, Varget, H4350, and IMR 4451, are some of the most successful propellants used by competitive shooters. If you want to find solid, reliable load data for these and other Hodgdon and IMR powders, we recommend you go right to the source — visit the Hodgdon/IMR Reloading Data Center, at www.HodgdonReloading.com. There you’ll find the latest, updated load recipes for pistol, rifle, and shotgun reloaders.

In the Data Center, you’ll find thousands of load recipes for pistol, rifle, and shotgun. Rifle shooters will find dozens of loads for their favorite Hodgdon, IMR, and Winchester powders such as H4198, Varget, H4350, and IMR 8208 XBR. And Hodgdon’s Reloading Center is now faster and easier to use. Navigation is simplified and the whole interface is more user-friendly.

Precise Search Results for your Cartridge and Favorite Powders
Hodgdon Reloading data Center hand loading powder

The online Reloading Data Center allows you to get precise search results for any listed cartridge. You can select your preferred powders and bullets. After choosing a cartridge, you can pre-select specific bullet weights and powder types. That quickly delivers just the information you want and need. You won’t have to scroll through scores of entries for bullets or powders you don’t use.

Data Center Works Well with Mobile Devices
Mobile users will notice Reloading Center is very “user-friendly” for smart-phone and tablet users. Controls have been optimized for touch-screens, and buttons are large and easy to use. Likewise the results are displayed in a large, easy-to read format.

Hodgdon tip from EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 2 Comments »