A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451. The results were very interesting, to say the least…
Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR offers a modern line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.
The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:
1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).
2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)
“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.
The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.
Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using BOTH a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. That provided two sets of velocity numbers. When placed and configured optimally, the LabRadar can measure muzzle velocity with +/- 0.1% accuracy, according to the manufacturer.
Here are the results from the PRB Powder Temp Stability Tests:
You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.
Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed. However, Alliant’s relatively new Reloder 16 is an extremely temp-stable powder, with a burn rate that is a close match to H4350. Many F-Open competitors are now using Reloder 16 with considerable success.
PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.
Do you know what the inside of a rifle chamber (and throat zone) really looks like? Do you understand the concept of headspace and why it’s important? If not, you should read the Brownells GunTech article Gauging Success – Minimum Headspace and Maximum COL. This article explains the basics of headspace and shows how to measure headspace (and length to lands) in your barrels with precision. The article also explains how to adjust your full-length sizing dies to “bump the shoulder” as needed.
Why is headspace important? The article explains: “Controlling headspace and setting proper C.O.L. also represent improved safety and reduced cost of handloading. Excessive headspace can cause case head separation and gases in excess of 60,000 PSI escaping from a rifle’s chamber. Too little headspace can result in a chamber forced bullet crimp and a bullet that becomes an obstruction more than a properly secured projectile. Excessive C.O.L. can result in a rifling-bound bullet, a condition that could result in spikes of excessive pressure.” [Editor’s NOTE: It is common for competitive benchrest shooters to seat bullets into the rifling. This can be done safely if you reduce your loads accordingly. With some bullets we often see best accuracy .010″ (or more) into the lands. However, this can generate more pressure than the same bullet seated .010″ away from initial lands contact. As with all reloading, start low and work up gradually.]
How is headspace specified? Most cartridges used within the United States are defined within ANSI/SAAMI Z299.3-4. Brownells explains: “In the case of the .243 Winchester, as an example, there are pressure specifications, cartridge drawings and, as pictured above, chamber drawings. Armed with a chamber drawing, each manufacturer producing a firearm for the .243 Winchester knows the proper standard dimension to cut chambers and set headspace. Notice there are two headspace reference dimensions for the chamber. The upper is a place in the chamber where the shoulder is .400″ in diameter; the “datum” or “basic” line. The lower is the 1.630″~1.640″ minimum – maximum dimension from the breech face (bolt face) to that point in the chamber that measures .400″.”
The actual headspace of any firearm is the distance from the breech face to the point in the chamber that is intended to prevent forward motion of a cartridge.
LabRadar owners can celebrate. New mobile-friendly control software is coming soon. Gunsmith and Benchrest Hall of Famer Thomas “Speedy” Gonzalez had some interesting news from the NRA Show in Dallas. He learned that the creators of the LabRadar chronograph systems will soon offer Mobile Apps that can run on your iOS or Android smartphone or tablet. This new software will make it much easier to control the LabRadar, and offer enhanced data editing functionality.
New LabRadar iOS and Android Mobile Apps Coming Soon…
Speedy says: “I just got back from the NRA show in Dallas, Texas. The coolest thing I personally saw at the show was at the LabRadar booth. They had the Beta versions of their new LabRadar Apps for the iPhone and Android phones. These Apps let you control all LabRadar functions from your phone as well as your tablet via Bluetooth connection. The new Apps will also allow the LabRadar owner to store and edit his or her data from a much larger and user friendly screen.”
That’s good news. We particularly like the ability to edit LabRadar data on a tablet. Speedy added: “This is going to revolutionize this great product and make it [much more] user-friendly.”
The new LabRadar Mobile Apps will be available free for LabRadar owners. If you own a LabRadar, be sure to register your LabRadar on the LabRadar Website. That will ensure you are notified via email as soon as the software is available. To register, look for the text link at the top right of the LabRadar homepage. It says “Register your LabRadar “. Click the link then fill out the data form.
Here’s a cool product that can help you level your front rest and rear bag, level your scope, align your target frame, and perform a myriad of tasks around the house. The Digital Angle Cube (aka Electronic Level and Protractor Gauge) is basically a high-tech level that gives you exact angular read-outs to within 0.2 degrees. That’s a lot more precise than any bubble level.
Numerous Shooting-Related Applications
For you position shooters who like to run angled sights, this tool will help you set the rear sight and front tower to exactly the same angle. For High Power guys with 3-way and 4-way adjustable buttstocks, this digital angle gauge can help you quickly and precisely set buttstock angle and cast-off.
Even tactical shooters and long-range hunters can use this device to confirm exact shot angle, with greater precision than a plastic protractor or even an expensive Angle Degree Indicator (ADI). Heck you can even use the thing as an anti-cant device (if you don’t mind the extra weight). We’re sure that our clever readers can find even more uses for a digital angle read-out tool.
The gray-faced iGaging Digital AngleCube sells on Amazon.com for $31.95. It comes with magnets on two sides so you can attach the tool to any ferrous metal surface for a “hands-free” reading. Amazon also sells the WATERPROOF Neoteck Digital Level for $24.95, with magnets on the base. You can find similar devices in hardware and home improvement stores. The illustration below shows how an INSIZE digital level and protractor can be used in the field.
New Zealand-based Annealing Made Perfect (AMP) has released powerful new software called AZTEC Mode. This works with existing AMP annealing machines, offering unrivaled “custom tuning” for your brass. AZTEC Mode lets AMP owners calibrate their own cases without sending samples to New Zealand. Basically you take one brass case from your lot, and AZTEC runs a special test cycle. You’ll discard that one case, but the software will analyze the brass characteristics and develop a custom, optimized annealing profile for that exact type of brass. We think the AMP machines were already the most advanced annealers on the market, and AZTEC Mode makes the AMP even better.
AMP’s engineers tell us: “This AZTEC system is not a firmware update or patch. It is a major upgrade in the way the annealer operates”. AZTEC Mode can be downloaded (in locked format) from AMPAnnealing.com, and you can install using the USB cable supplied with the annealer. When downloaded, it will be locked. The Unlock Code can be purchased for $250.00 from Creedmoor Sports.
This 4-minute video explains the basic features of AZTEC mode:
Patent-Pending AZTEC Mode software has been under development for quite some time. This very sophisticated software was unveiled at SHOT Show 2018, and now it is available for download and purchase. AMP’s team has worked hard in the past few months perfecting AZTEC Mode and it’s now ready for the end user. Watch this comprehensive video to see how AZTEC Mode works.
Here is a full 23-minute Instructional Video on AZTEC Mode:
AZTEC also comes with a “Sort Mode” comparator, which analyses the neck, shoulder and front section of the body. It is very sensitive to variables such as mass and dimensions. It is a work in progress. Annealing Made Perfect are conducting further research with ballistics laboratories to establish the best applications. AZTEC Mode is self-prompting and very simple to use with minimal technical expertise. AMP has prepared instructional videos showing how to install and use AZTEC Mode. You don’t have to be a computer whiz — just follow the instructions and you should find AZTEC pretty easy to use.
To buy AZTEC Mode software, use the USB cable supplied with the annealer and download the AZTEC Mode Software from AMPAnnealing.com. Then purchase the Unlock Code from Creedmoor Sports for $250.00. Customers will then receive an email from Annealing Made Perfect with the unlock code and instructions within 48 hours. AZTEC Mode is currently only available for Windows OS, with a version for Apple (Mac) iOS available soon.
Did you know you can damage your hearing even if you are wearing the best hearing protection available? Well, have you ever heard of concussion (or concussive) hearing loss? There is no amount of anything you can put in or over your ears to protect you from concussion loss. My audiologist explained to me the concussion comes through the facial bone structure and damages the ear’s tiny bones.
Editor’s NOTE: This may be the most important tech article we’ve run all year. It explains how you can suffer inner ear damage and hearing loss even if you use earplugs or muffs. Read that again — hearing loss even with typical hearing protection. This kind of concussive hearing loss can result from shooting with muzzle brakes in confined spaces. Using a suppressor (aka sound moderator) can reduce the risk of concussive hearing loss. You may not have the ability to use a suppressor, but this article explains how you should be more mindful of your hearing.
Why I Use a Suppressor (Preventing Concussive Hearing Loss)
It must have been the road noise. I thought I was having a hard time hearing my five year old daughter speaking to me on my cell phone because of the road noise. That old SUV was kind of loud inside. Until I switched the phone to my left ear and suddenly I could hear her just fine. Wait, what just happened? I moved the phone back to the right ear and there was that muffled voice again. That’s when I knew I had a problem.
“What?” Lots of us in the shooting community have lost some hearing along the way due to our time on the range or in the field. Those of us who hunt have certainly discharged a firearm or three without ear protection and without concern for our hearing. After all, it’s just one shot, right? How much can it hurt?
Actually, that one shot DOES hurt your hearing. Any sound over 140 dB is immediate hearing loss. It just happens to be killing a small amount of our hearing so most of us continued the practice without a care. Living with hearing loss now makes me wish I could go back 20 years and better protect my hearing. I can’t change what I did in the past, but going forward I can certainly do the most to protect the hearing I still have.
I decided to shoot about a year’s worth of matches with just braked rifles. That year is when I lost significant hearing in my right ear and some in the left. I’ve gone back to shooting only suppressed rifles whenever possible.
I shot my first suppressed firearm, a .22 LR pistol, in 2003. After a few rounds I wondered why everyone (who can do so legally) didn’t shoot suppressed? No one drives without a muffler. Why would you? Point is I immediately appreciated the hearing protection benefits of suppressors. That passion got me into the business of selling suppressors and it wasn’t long before I was one of the biggest retailers for companies like AAC, SWR, SilencerCo, Ops Inc. and others. [Editor: The author’s business, Accurate Ordnance, no longer sells suppressors. So this article is NOT a sales pitch. Mark just wanted to share his experience so others might protect their hearing.]
Did you know you can damage your hearing even if you are wearing the best hearing protection available? You’ve heard guys say, “I’ll wear plugs and muffs, so I’ll be just fine shooting that .50 BMG!” Well, ever heard of concussion (or concussive) hearing loss? Yeah, I hadn’t either. I’ll sum it up the way the last audiologist I spoke with about my hearing loss did – there is no amount of anything you can put in or over your ears to protect you from concussion loss.
A hand grenade went off right next to a buddy of mine. He lost some hearing as a result of the blast. No one is really surprised by that. I mean it is an EXPLOSION. It’s loud. Duh. But I had no idea the blast from a muzzle brake could basically hurt my hearing the same way. The doctor explained to me the concussion comes through the facial bone structure and damages the ear’s tiny bones. Same thing as what can happen through any TBI (traumatic brain injury).
I’ve owned quite a few different suppressors over the years and have shot just about everything out there. I’m still as big a fan as ever. However, I wanted to see if using a suppressor in PRS (Precision Rifle Series) and similar matches was actually a hindrance. Some people feel the added length and weight of a suppressor can make getting into some shooting positions slower or problematic. So I decided to shoot about a year with a muzzle brake instead of a suppressor. I sure regret that decision…
Getting Headaches at PRS Matches Was Warning Sign
It is fairly common in PRS matches to shoot through pipes, vehicles, inside “shoot houses” and around other obstacles that echo a rifle’s blast. I noticed I was starting to get headaches about halfway through a day of PRS match shooting. I knew the issue wasn’t hydration. I mean look, if you are peeing every other stage down at the amazing CORE range facility in mid-summer you are NOT dehydrated. So, what was causing the headaches? It wasn’t until I went back to shooting suppressed in those same environments that it became clear the little mini concussions from that muzzle brake was causing my headaches. And of course the doctors confirmed that.
Let me stop here and say I am NOT anti-brake. Muzzle brakes are useful tools and for some situations are the best tools. An aggressive brake can be more effective at reducing recoil than a good suppressor. A suppressor does add some recoil reduction, just not as much as most quality brakes. Don’t forget to factor other variables, such as caliber and rifle weight, into the equation though. For example, a 15-lb 6mm Creedmoor rifle doesn’t need much recoil reduction in the first place.
So, I started shooting matches long before the PRS even existed and always shot suppressed in those days. The suppressors made communication with a partner or RO easier and it was just a more pleasant shooting experience. On the recommendations of a few people I decided to shoot about a year’s worth of matches with just braked rifles. That year is when I lost significant hearing in my right ear and some in the left. I’ve gone back to shooting only suppressed rifles whenever possible and especially at matches. I’ve only once or twice found the extra length of the suppressor made it a little more inconvenient to run a stage, but not by much. Trust me, the points I missed were not because I took two extra seconds getting the muzzle in a port or window.
My hearing is something I value and will do everything to protect from this point forward. You’ll never again see me on a match field with an un-suppressed rifle. To me the minimal gains of running a braked rifle aren’t worth losing more hearing.
Choosing a Suppressor — What to Consider
Okay, so I have hearing loss that I can’t get back and realize I need to go back to shooting matches with a suppressor. But which one? I’ll still be shooting matches with custom fit plugs so I just need something to add a little recoil reduction and kill that concussion.
At our shop, Accurate Ordnance, we generally recommend direct-thread suppressor solutions to our customers. The main reason for that is all the problems we’ve seen with other fast-attach muzzle devices. It doesn’t take much tolerance stacking to result in accuracy issues. There are a few exceptions for us and the Rugged Suppressors products top the list. Since the Razor 762 uses a muzzle brake adapter on the rifle to attach the suppressor, I can use the same suppressor on my .223 Rem training rifle. My primary match rifles are chambered in 6mm Creedmoor and 6.5 Creedmoor and the muzzle threads on those is a standard 5/8×24. My .223 Rem training rifle has .5×28 threads on the muzzle, which is standard for that caliber. Thus, the muzzle adapter interface lets me share the suppressors between all the rifles. And on that .223 Rem training rifle I have the option of switching the end cap on any of the Rugged products to a .223 aperture size, which makes the suppressors slightly more sound efficient (meaning quieter).
Many shooters these days clean their cartridge brass ultrasonically, or wet-tumble their cases with stainless media (above). Both methods get brass clean and shiny, inside and out. However, when those wet-cleaning processes are completed, you’re left with a pile of soaking wet brass. How do you dry your brass quickly and efficiently, without unsightly water spots? Read on for some great answers…
In our Shooters’ Forum, Forum Gold Member Terry asked: “How do you dry your brass after Ultrasonic cleaning?” In an interesting Reloading Forum Thread, many smart suggestions were posted. A dozen fellow members outlined a variety of effective case-drying procedures, which work equally well for both wet-tumbled brass and ultrasonically-cleaned cases. Here are the Top 10 brass-drying suggestions from our Forum members.
TOP TEN Ways to Dry Cartridge Brass After Wet Cleaning
1. Food Dehydrator — Shake the brass in towel to get the bulk of water off. Next leave in the food dehydrator for 45 minutes or until there are no signs of moisture inside the cases. — Lawrence97
2. Lyman 5-Level Case Dryer — Rinse off cleaning solution(s), then load brass by type into racks in Lyman Cyclone Case Dryer. This is easier to load/unload than food dehydrators and holds more cases.
3. Hot Water + Compressed Air — Rinse all your cases as a batch using scalding hot water from the kitchen sink. Hot water evaporates off of brass very very quickly. Then hit them with compressed air. Takes 10 minutes. Simple. — SG4247
4. Oven Dry in Pre-Heated Oven — After pre-heating to 200° or so, turn off oven and put brass inside on a tray. Most important! Tell your wife what you are doing so she doesn’t crank it up to 425 to heat pizza! — MClark
NOTE: Many other members suggested oven drying at 150-200°. We recommend turning OFF the oven so you don’t cook your brass if you forget to remove the cases.
5. Towel Dry then Warm with Heat Gun — Roll brass in a towel until no more water shakes out. Lay out on cardboard box top and blow off with Harbor Freight heat gun. $9.99 on coupon. Two minutes of heated air and about half hour of wait and they are good to go. This is with primers removed. — Shaggy357
6. Compressed Air, then Sun Dry Outside – I rinse the brass, then blow them out with compressed air. Then, dependent on the time of year, lay them on a towel in the sun. — HogPatrol
7. Dishwasher on Dry Cycle – In the winter, I drop my wet brass cases neck-down on the rack pegs in the dishwasher, then turn on the dry cycle. In the summer…well, I’m in Texas. They go to the porch for a bit. — Toolbreaker
8. Alcohol Rinse then Air or Oven Dry — Rinse in 90% Isopropyl alcohol and either let air dry or stick in 175° oven for half an hour. Alternatively, use a dehydrator. — Zipollini
9. Slow Air-Dry in Loading Blocks — I have a reloading block with holes drilled in it. I simply load the block up and let it air-dry in the cupboard for a couple of days. — JCS
10. Wipe with Towel Then Anneal Normally — This thread is stirring my OCD side. Seems complicated for just drying — my brass dries just fine when I anneal it. This entire process can’t take an hour per batch. When finished, the brass is cleaned, annealed, and ready to size. — CHLuke
Deprime, then tumble brass with stainless media, water, Lemishine, and dish detergent.
Shake them easily in a strainer to knock out most media then grab 4-5 pieces, shake them over the bucket for the last of the media then inside a towel.
Finally blow out the primer pockets and wipe with a towel, load in the Annealeez.
OK, admit it — you’ve always wondered how they get those color swirls and camo patterns in McMillan stocks. (You’ll be surprised at the answer). And how does McMillan manage to inlet stocks so precisely for so many different action types?
McMillan Stocks is one of the leading fiberglass stock producers, cranking out 8,000-10,000 stocks every year for hunters, target shooters, and members of the military. McMillan employs state-of-the-art, high-tech machinery. At the same time, many processes are still done by hand — such as applying colors to the stocks.
In the videos below, Kelly McMillan hosts Bob Beck of Extreme Outer Limits TV in a tour of the McMillan stock-making facility. We think all avid “gun guys” will be fascinated by these high-quality videos.
McMillan Custom Stock Production
The first video shows the stock-building operation from start to finish — You’ll see the lay-up, color application, molding, and “stuffing”. Watch carefully at 0:16 to see colors being applied.
How and Why to Create a Dummy Round
When you have a new custom rifle built, or a new barrel fitted to an existing rifle, it makes sense to create a dummy round. This should have your preferred brass and bullet types, with the bullet positioned at optimal seating depth. A proper dummy round helps the gunsmith set the freebore correctly for your cartridge, and also ensure the proper chamber dimensions.
Respected machinist, tool-maker, and gunsmith Greg Tannel of Gre-Tan Rifles explains: “I use the dummy round as a gauge to finish cut the neck diameter and throat length and diameter so you have [optimal] clearance on the loaded neck and the ogive of the bullet just touches the rifling.” He recommends setting bullet so the full diameter is just forward of the case’s neck-shoulder junction. “From there”, Greg says, “I can build you the chamber you want… with all the proper clearances”.
Greg Tannel has created a very helpful video showing how to create a dummy round. Greg explains how to measure and assemble the dummy and how it will be used during the barrel chambering process. Greg notes — the dummy round should have NO Primer and No powder. We strongly recommend that every rifle shooter watch this video. Even if you won’t need a new barrel any time soon, you can learn important things about freebore, leade and chamber geometry.
This has been a very popular video, with 244,000 views. Here are actual YouTube comments:
That is the best explanation I’ve ever seen. Thank you sir. — P. Pablo
Nice video. You do a very good job of making this easy for new reloaders to understand. I sure wish things like this were available when I started reloading and having custom rifles built. Once again, great job, and your work speaks for itself. — Brandon K.
Beautiful job explaining chambering clearances. — D. Giorgi
Another Cool Tool — The Stub Gauge
When you have your gunsmith chamber your barrel, you can also have him create a Stub Gauge, i.e. a cast-off barrel section chambered like your actual barrel. The stub gauge lets you measure the original length to lands and freebore when your barrel was new. This gives you a baseline to accurately assess how far your throat erodes with use. Of course, as the throat wears, to get true length-to-lands dimension, you need take your measurement using your actual barrel. The barrel stub gauge helps you set the initial bullet seating depth. Seating depth is then adjusted accordingly, based on observed throat erosion, or your preferred seating depth.
This barrel’s shoulder was 0.025″ off the action because Red Locktite had been used on the threads.
Gunsmith Thomas ‘Speedy’ Gonzales offered this interesting report about how NOT to headspace a barrel. Hopefully you never discover something like this…
“A good friend and customer sent this rig in for repair after FedEx damaged the rifle during inbound transport from another smith. After repairing the stock and rebedding it, I decided to re-polish the barrel to make the repair perfect. Well this just added insult to injury as the barrel did not want to come off. After a few choice words, the barrel finally broke free only to reveal something very disturbing. It seems the barrel had been ‘headspaced’ by using RED Loctite to hold it in place.” [Editor: That’s definitely NOT how barrels should be fitted.]
Speedy was not happy: “I hope the smith that did this sees the photos and realized what jeopardy he put my customer in or anyone who shot the rifle for that matter. When cleaned up, the shoulder on the barrel was over 0.0250″ (25 thousandths) away from the face of the receiver.” [Editor: That’s a lot in this business]. Check out the images below to see how much the barrel rotated further inward when cleaned up. The barrel spun in nearly another eighth-turn or more. Not good.
Speedy says: “I just got back from the NRA show in Dallas, Texas. The coolest thing I personally saw at the show was at the LabRadar booth. They had the Beta versions of their new LabRadar Apps for the iPhone and Android phones. These Apps let you control all LabRadar functions from your phone as well as your tablet via Bluetooth connection. The new Apps will also allow the LabRadar owner to store and edit his or her data from a much larger and user friendly screen.”
5. Towel Dry then Warm with Heat Gun — Roll brass in a towel until no more water shakes out. Lay out on cardboard box top and blow off with Harbor Freight heat gun. $9.99 on coupon. Two minutes of heated air and about half hour of wait and they are good to go. This is with primers removed. — Shaggy357
OK, admit it — you’ve always wondered how they get those color swirls and camo patterns in McMillan stocks. (You’ll be surprised at the answer). And how does McMillan manage to inlet stocks so precisely for so many different action types?
