February 7th, 2016

Tuning Balance-Beam Scales For Precision and Repeatability

Tuning Balance Beam Scale

While many folks enjoy the convenience of an electronic powder scale/dispenser such as the RCBS Chargemaster, some hand-loaders still prefer to use a traditional balance beam. Balance beam scales are simple, compact, and don’t suffer from electronic “glitches”. Moreover, even if you use a digital dispenser at home, when you’re doing load development at the range, a balance-beam scale may be more convenient. A scale doesn’t require electrical power, so you don’t need to bring battery packs or string long power cables. Just bring some kind of box to shelter your beam scale from the wind.

While designs like the RCBS 10-10 are decent performers as built, they can be made much more precise (and repeatable), by “tuning” of key parts. Forum member Scott Parker (aka SParker) optimizes a variety of popular beam scales, including the Ohaus 10-10 (USA-made model), RCBS 10-10 (USA-made model), RCBS 5-10, Lyman M5, Lyman D5, and others. You send Scott your scale, he tunes the key components, tests for precision and repeatability, and ships it back to you. The price is very affordable (under $85.00).

Scott tells us: “I have tuned several 10-10s. They all have turned out very sensitive, consistent and hold linearity like a dream. If only they came that way from the factory. The sensitivity after tuning is such that one kernel of powder registers a poise beam deflection. For repeatability, I remove the pan and replace it for the zero 10 times. The zero line and the poise beam balance line must coincide for each of those 10 tries. I then set the poises to read 250.0 grains. I remove and replace the pan 10 times with the calibration weight. For linearity, the poise beam balance line and the zero line should coincide within the line width. This is roughly one half a kernel of powder. For repeatability, the poise beam balance line must return to that same balance point ten times. I then adjust the poises back to zero and recheck the zero. I have a master’s degree in chemistry, thus I am very familiar with laboratory balances. Email me at vld223 [at] yahoo.com or give me a call at (661) 364-1199.”

The video above, created by British shooter Mark (aka 1967spud), shows a 10-10 beam scale that has been “tuned” by Scott Parker. In the video, you can see that the 10-10 scale is now sensitive to one (1) kernel of powder. Mark also demonstrates the’s scale’s repeatability by lifting and replacing a pan multiple times. You can contact Mark via his website, www.1967spud.com. To enquire about balance-beam scale tuning, call Scott Parker at (661) 364-1199, or send email to: vld223 [at] Yahoo.com.

Video tip from Boyd Allen. We welcome reader submissions.
Permalink Reloading, Tech Tip 3 Comments »
February 3rd, 2016

Six Ways to Save Money for Your Shooting Hobby

Saving Money on Shooting expenses

For many Americans, real incomes have stayed flat in recent years, while the true cost of living has risen. Accordingly, it’s important to save money whenever possible. Prices are going up, but wages aren’t following (for most of us). Here are six ways shooters can save money on gear purchases and other shooting-related expenses.

1. Check Out the Forum Classifieds. There are great deals to be found every day in the AccurateShooter Shooters’ Forum. The latest deals are displayed in the right column of every Forum page. To see all the listings, browse through the Forum MarketPlace section which has four main categories:

  • Guns, Actions, Stocks, & Barrels
  • Tools, Dies, Rests, Reloading Components & Misc
  • Scopes, Optics, Sights, Rings, Bases Etc.
  • Commercial Sales by Paid Sponsors

2. Use Discount Codes to Save. It’s always smart to check for discount codes before you buy. In the Daily Bulletin, we feature “Deals of the Week” every Monday morning, and we provide discount Coupon Codes when available. These can reduce the price substantially or lower shipping costs. Search codes for Brownells, Sinclair Int’l, Cabela’s, and Amazon.com. Check your email also — some discount codes are only announced in email newsletters. If you can’t find a Coupon Code for your preferred vendor, visit RetailMeNot.com and/or SlickGuns.com. Both those sites list current coupon codes, and RetailMeNot.com covers thousands of vendors.

3. Shop for “Demo” Optics. Modern high-quality optics can easily cost $1500.00 or more, often exceeding the value of the rifle on which they are mounted. However, you can often save 20-30% by purchasing demo optics. These are normally display units used at trade shows. They may have slight ringmarks, but otherwise they are “as new”, having never been carried in the field or used on a rifle that has fired live ammo. When purchasing demo scopes, you should always ask about the warranty before consummating the sale. However, most demo scopes from name-brand manufacturers come with full factory warranties. EuroOptic.com and SWFA.com are two respected vendors that offer a good selection of demo optics.

4. Train with Rimfire Rifles. The true cost of shooting a match-grade centerfire rifle, when you consider barrel wear, approaches $1.00 per round. READ Shooting Cost Article. By contrast, decent .22LR target ammo sells for under $0.19 per round (though it is, admittedly, hard to find right now). Good rimfire barrels last a long, long time, so you don’t have to be concerned about wearing out your barrel quickly. A quality rimfire barrel can retain its accuracy for 7,000 rounds or more. If you run the ballistics, a .22LR round at 100 yards can emulate the wind drift experienced by a centerfire cartridge at long range. This allows for effective cross-training with much less expensive ammo.

5. Take Advantage of Factory Rebates. There are some attractive rebates available right now from quality manufacturers such as Bushnell, Leupold, RCBS, and Zeiss. You have to be a bit wary because rebates are typically used to move less-popular merchandise. But some rebates, such as the RCBS ‘Buy Green, Get Green’ Promo, apply to very wide range of merchandise, so it’s hard to go wrong. Just make sure that, when you buy a product, you retain the sales slip and the original packaging (it’s also wise to print out online orders). To qualify for the rebate, you may need to mail in a product identification code found on the box, along with your original sales receipt.

6. Share a Ride to Matches. Gas prices have fallen dramatically in the past year, but fuel remains a significant part of a shooter’s hobby budget, particularly if you drive long distances to compete at major matches. We’d say 90% of shooters drive solo to matches, often in large, gas-guzzling trucks. If you drive 200 miles round-trip to attend a match in a 20-mpg vehicle, you’ll burn nearly $30.00 worth of gasoline on your trip. That adds up. By simply sharing the ride with one fellow shooter you can cut your fuel expenditures in half. And, if you alternate vehicles from one match to the next, you also save on wear and tear on your own vehicle. At $0.50/mile consider the savings.

Permalink Competition, Tech Tip No Comments »
February 2nd, 2016

6.5mm Cartridges — Eight Options to Consider

6.5 Cartridge Guide Eben Brown EABco e. arthur brown 260 rem 6.5x47 6.5 creedmoor 6.5x55
Chart created with Ammoguide’s Visual Comparison Tool. Visit Ammoguide.com to learn more.

One of our forum members was looking for a very accurate, mid-sized 6.5mm cartridge for target working and coyote hunting. There are many great options including the 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor, and Remington .260 (a 6.5-08). If you are considering the 6.5×47 you should read our 6.5×57 Cartridge Guide authored by the 6.5 Guys. This and other 6.5mm cartridges are covered in this introduction to 6.5 mm cartridges prepared by Eben Brown, President of Eabco.com.

Guide to 6.5mm Cartridges

by Eben Brown, EABCO.com, (E. Arthur Brown Co. Inc.)
The current popularity of 6.5mm cartridges in the USA has been a long time in coming. I won’t go into my opinions on why it took so long to catch on. The important thing is that it finally HAS caught on and we’re now so fortunate to have a wide selection of 6.5mm cartridges to choose from!

6.5mm Grendel – Developed by Alexander Arms for the AR15 and military M4 family of rifles. The Grendel fits the dimensional and functional requirements of these rifles while delivering better lethality and downrange performance. There are now similar cartridges from other rifle companies. We chamber for the Les Baer “264 LBC-AR”. Designed for velocities of 2400-2500 fps with 123gr bullets, it shoots the 140-grainers at about 2000 fps (for comparison purposes).

6.5mm BRM – Developed by E. Arthur Brown Company to give “Big Game Performance to Small Framed Rifles” — namely our Model 97D Rifle, TC Contender, and TC Encore. Velocities of 2400-2500 fps with 140gr bullets puts it just under the original 6.5×55 Swede performance.

6.5x47 Lapua Cartridge guide

6.5mm x 47 Lapua – Developed by Lapua specifically for international 300m shooting competitions (with some interest in long-range benchrest as well). Case capacity, body taper, shoulder angle, and small rifle primer are all features requested by top international shooters. You can expect velocities of 2500-2600+ with 140 gr bullets.

6.5mm Creedmoor – Developed by Hornady and Creedmoor Sports, the 6.5mm Creedmoor is designed for efficiency and function. Its shape reaches high velocities while maintaining standard .308 Winchester pressures and its overall length fits well with .308 Win length magazines. You can expect velocities of 2600-2700+ fps with 140gr bullets.

.260 Remington – Developed by Remington to compete with the 6.5mmx55 Swedish Mauser that was (finally) gaining popularity in 1996. By necking down the 7mm-08 Remington to 6.5mm (.264 cal), the .260 Remington was created. It fit the same short-action [receivers] that fit .308 Win, .243 Win, 7mm-08 Rem, etc. You can expect velocities of 2600-2700 fps with 140gr bullets in the 260 .Remington.

[Editor’s Note: In the .260 Rem, try the Lapua 120gr Scenar-Ls and/or Berger 130gr VLDs for great accuracy and impressive speeds well over 2900 fps.]

6.5mm x 55 Swedish Mauser – This was the cartridge that started the 6.5mm craze in the USA. It is famous for having mild recoil, deadly lethality on even the biggest game animals, and superb accuracy potential. Original ballistics were in the 2500 fps range with 140gr bullets. Nowadays handloaders get 2600-2700+ fps.

[Editor’s Note: Tor from Scandinavia offers this bit of 6.5x55mm history: “Contrary to common belief, the 6.5×55 was not developed by Mauser, but was constructed by a joint Norwegian and Swedish military commission in 1891 and introduced as the standard military cartridge in both countries in 1894. Sweden chose to use the cartridge in a Mauser-based rifle, while Norway used the cartridge in the Krag rifles. This led to two different cartridges the 6.5×55 Krag and 6.5×55 Mauser — the only real difference being safe operating pressure.”]

6.5-284 Norma — This comes from necking the .284 Winchester down to .264 caliber. Norma standardized it for commercial ammo sales. The 6.5mm-284 was very popular for F-Class competition and High Power at 1,000 yards. However, many F-Class competitors have switched to the straight .284 Win for improved barrel life. 6.5-284 velocities run 3000-3100+ fps with 140gr bullets.

.264 Winchester Magnum – Developed by Winchester back in 1959, the .264 Win Mag never really caught on and may have delayed the ultimate acceptance of 6.5mm cartridges by US shooters (in my opinion). It missed the whole point and original advantage of 6.5 mm cartridges.

The Original 6.5mm Advantage
The special needs of long-range competition have skewed things a little. However the original advantages of 6.5mm cartridges — how deadly the 6.5mms are on game animals, how little recoil they produce, and how easy they are to shoot well — still hold true today.

6.5 Cartridge Guide Eben Brown EABco e. arthur brown 260 rem 6.5x47 6.5 creedmoor 6.5x55

Permalink Bullets, Brass, Ammo, Tech Tip 6 Comments »
January 30th, 2016

Primer Cratering Problem? Give Greg Tannel a Call…

Crater moon primers greg tannel bushing firing pinCraters may look interesting on the moon, but you don’t want to see them on your primers. Certain mechanical issues that cause primer craters can also cause primer piercing — a serious safety problem that needs to be addressed. If you have a gun that is cratering primers (even at moderate pressure levels), there is a solution that works with many rifles — send your bolt to Greg Tannel to have the firing pin hole bushed.

Shooters who convert factory actions to run 6BRs, 6PPCs or other high-pressure cartridges should consider having the firing pin bushed. These modern cartridges like to run at high pressures. When running stout loads, you can get cratering caused by primer flow around the firing pin hole in the bolt face. The reason is a little complicated, but basically the larger the hole, the less hydraulic pressure is required to crater the primer. A limited amount of cratering is normally not a big issue, but you can reduce the problem significantly by having a smith fit a bushing in the firing pin hole. In addition to reduced cratering, bushing the firing pin often produces more consistent ignition.

CLICK HERE for Gre-Tan Firing Pin Bushing Service INFO

This is a highly recommended procedure that our editors have had done to their own rifles. Greg Tannel (Gre-Tan Rifles) is an expert at this procedure, and he does excellent work on a wide variety of bolts. Current price for a bushing job, which includes turning the firing pin to .062″, is $80.00, or $88.00 with USPS Priority Mail return shipping.

If you have a factory rifle, a bushed firing pin is the way to go if you are shooting the high-pressure cartridges such as 6PPC, 6BR, 6-6.5×47 and 6.5×47. This is one of the most cost-effective and beneficial upgrades you can do to your factory rifle. For more info on the Firing Pin Bushing process, visit GreTanRifles.com, or email greg [at] gretanrifles.com. (After clicking the link for GreTanRifles.com, Click on “Services” > “Shop Services” > “Bolt Work”, and you’ll see a listing for “Bush Firing Pin Hole & Turn Pin”. Select “View Details”.)

Gre-Tan Rifles firing pin bushingFiring Pin Hole Bushing by Greg Tannel

Work Done: Bush firing pin hole and turn pin.
Functions: Fixes your cratering and piercing problems.
Price: $80.00 + $8.00 return shipping
Total Price: $88.00

Actions for which Bushing is Offered: Remington, Winchester, Savage multi-piece pin, Sako, Kimber, Nesika, Stiller, BAT Machine, Kelbly, Lawton, Surgeon, Borden, Wichita, Hall, Ruger, Howa, Weatherby, Dakota, Pacific Tool, Phoenix, and Defiant bolt action rifle or pistol.

Actions for which Bushing is NOT Available: Case hardened receivers, ARs, Accuracy International (AI), Barnard, Big Horn, Cooper, Desert Tactical Arms, Kimber, Rosenthal, New Savage single piece pin, Rim fires, Falling block, Break open, Lever, Pump rifles, 1903-A3, CZ, Mauser.

How to send your bolt in to be bushed:
You can send your bolt snail mail, priority mail, or UPS (Please do not use FEDEX as it sometimes has delivery delays). Pack your bolt carefully and ship to: Gre’-Tan Rifles, 24005 Hwy. 13, Rifle CO 81650. Please include your name, phone number, and return shipping address.

Due to the high volume of work, turn around is 5 to 8 weeks on bushing a bolt. Three or more bolts will be sent back to you UPS and we will have to calculate shipping. We can overnight them at your expense. You can pay by check, money order, or credit card. For more information visit GretanRifles.com.

Permalink Gunsmithing, Tech Tip 4 Comments »
January 27th, 2016

Tech Tip: Wash Bottles Speed Barrel Cleaning

rifle bore cleaner bottleOne of our Forum readers complained that his 6mm jags fit very tight with patches, making it difficult to apply much solvent. The problem with a tight-fitting patch is that the solvent gets squeezed off in the first few inches. You can switch to a smaller jag, or a bore mop, but there is an even better way to get an ample amount of solvent in your bore — just spray it in with a “wash bottle”. This is an inexpensive plastic bottle with an L-shaped dispensing neck, tapered at the end. You can either just plug the breech and spray from the muzzle end (where most copper fouling is), or, alternately, put the wash bottle neck directly in the chamber and spray forward. When spraying from the chamber forward, you may need to use a rubber O-Ring to seal off the action… depending on the bore size and the particular wash bottle’s neck spout diameter.

Bottle Solvent Application Great for Smaller Bores
Using wet patches or wet brushes is an inefficient way to really saturate the tight bores of 17s, 20s, and 22s. Even with a cotton bore mop, most of the solvent will be squeezed out before it gets to the end of the bore, where most copper fouling occurs. For these smaller 17, 20, and 22-caliber bores, you can just take the “wash bottle” and stick the tapered nozzle right in the chamber. The tapered end will press fit in the throat, sealing off the chamber. With the barrel slightly nose-down, give the bottle a couple good squirts until the solvent mists out the muzzle. In just a few seconds, this will put more solvent in the bore than a half-dozen wet patches.

A solvent-filled wash bottle is also handy for wetting your brushes. It’s much easier to saturate a bore brush (without spilling solvent on your stock), by using the wash bottle. You can get wash bottles from USPlastic.com, Amazon.com, or lab supply stores.

Permalink Tech Tip 16 Comments »
January 24th, 2016

Rifle Barrel Cleaning 101 — The Criterion Way

Editor: This article appears on the Criterion Barrels website. It provides good, conservative advice about barrel cleaning. Understand that cleaning methods may need to be adapted to fit the amount and type of fouling (and the particular barrel). In general, we do try to minimize brushing, and we follow the procedures Criterion recommends respecting the crown/muzzle. We have also had very good success using wet patches followed by Wipe-Out bore foam. Along with the practices outlined by Criterion below, you may want to try Wipe-Out foam. Just be sure to use a fitted cleaning rod bore guide, to keep foam out of the action recesses and trigger assembly.

Criterion Barrels Cleaning Clean Solvent rod guide Hoppes Wipe-Out

What is the Best Way to Clean a Rifle Barrel?

We are asked this question quite frequently alongside requests for recommended break-in procedures. Improper barrel cleaning methods can damage or destroy a barrel, leading to diminished accuracy or even cause a catastrophic failure. When it comes to barrel maintenance, there are a number of useful techniques that we have not listed. Some techniques may work better with different barrel types. This series of recommendations is designed to incorporate a number of methods that the Criterion Barrels staff has used successfully both in the shop and on their personal rifles. Please feel free to to list your own recommendations in the below comments section.

We recommend the use of the following components during rifle cleaning:

• Cloth patches (sized for the appropriate caliber)
• Brass jag sized properly for your bore
• One-piece coated cleaning rod
• General bore cleaner/solvent (Example: Hoppes #9)
• Copper solvent of your choosing (Example: Sweets/KG 12)
• Fitted cleaning rod bore guide
• Plastic AP brush or toothbrush
• Q-Tips
• Plastic dental picks
• CLP or rust preventative type cleaner

There are a number of schools of thought relating to the frequency in which a barrel should be cleaned. At minimum we recommend cleaning a barrel after each shooting session to remove condensation, copper, and carbon build-up. Condensation is the greatest immediate threat, as it can cause the barrel to rust while the rifle sits in storage. Copper and carbon build-up may negatively impact future barrel performance, increasing the possibility of a failure in feed or function. Fouling should be removed whenever possible.

The below tips will help limit the wear of different parts of your barrel during routine maintenance, helping extend the life of the barrel and improving its performance.

The Crown
The crown is the portion of the barrel where the bullet loses contact with the lands and grooves and proceeds to exit the firearm. The area most critical to accuracy potential is the angle where the bullet last touches the bore of the barrel.

Avoid damage to this area by using a plastic toothbrush and CLP type cleaner to scrub the crown from the exterior of the barrel. Even the most minimal variation in wear to the crown will negatively impact barrel performance, so be careful to avoid nicking or wearing away this part of the barrel.

Reducing Cleaning Rod Wear to the Crown
When running a patch through the barrel, place the muzzle about a ¼” from a hard surface that runs flat at a perpendicular angle to the cleaning rod’s direction of travel, like a wall or the edge of a work bench (pictured). When the jag impacts the hard surface, retract the cleaning rod and remove the patch.

By withdrawing the jag prior to its exit from the barrel, you are limiting the possibility of the brass dragging upon the crown if the rod is at all bent or misaligned. The soft cloth patch will continue to serve as the point of contact between the jag and the barrel, minimizing potential wear.

If possible, insert the rod through the chamber, pushing it forward toward the muzzle. Some rifles, such as the M1 Garand or M14, will require you to insert the cleaning rod through the muzzle. In these situations the use of a cleaning rod guide is recommended to limit the friction placed upon the crown.

Avoid using cleaning rod segments for scraping carbon from the recessed muzzle of an AR-15 barrel. We used this trick in the Marine Corps to impress the armorers and NCO’s with the cleanliness of our muzzles, but it likely played a significant role in reducing the service life of the rifle barrel in question.

Use a Q-Tip soaked in solvent to remove any copper or carbon residue from the recessed muzzle of an AR-15 barrel. A little bit of remaining carbon on the face of the muzzle will not negatively affect bullet travel so long as the crown edge remains consistent around the circumference of the bore.

The Lands and Grooves
This portion of the barrel may experience reduced efficiency due to copper fouling and cleaning rod damage. If copper fouling takes place during the initial break-in of the rifle, make sure to check our barrel break-in article.

For regular maintenance we suggest using a single piece coated cleaning rod rather than the traditional segmented rod or bore snake. While segmented rods and bore snakes may be convenient for field use, the corners between the segments may bow out and catch on the lands, scraping along the length of the rifling. Residual grit and particles from expended cartridges may also get caught between segments, resulting in an abrasive surface working its way down the length of the barrel. Most bore snakes will remove significant amounts of carbon fouling, but may fall short in the removal residual carbon buildup and copper fouling during deep cleaning. Good rods can be sourced from multiple manufacturers, but we have found good results using both Pro-Shot and Dewey brand products.

General cleaning requires the use of patches rather than nylon or brass bore brushes. Brass brushes may be required when aggressive cleaning is required, but can lead to unnecessary wear on the barrel if used frequently. This is not due to the nature of the soft brushes themselves, but from the abrasive particles of grit that become embedded in the material that is being run repeatedly through the bore. We recommend the use of bore guides when cleaning from both the muzzle and breech. These bore guides will help serve to protect the crown and throat from cleaning rod damage.

If significant resistance develops while running the cleaning rod through the bore, no attempt should be made to force it in further. Back the rod out and inspect the barrel to determine the cause of the resistance. The jag may be pushing between a bore obstruction and the rifling, digging a divot into the barrel before pushing the obstruction back through the muzzle. One way to minimize the risk of a stuck rod is by utilizing a slightly smaller patch during the initial push.

The process of cleaning the length of the rifling is relatively straightforward:

1. Check to make sure the rifle is safely unloaded.
2. Carry out any necessary disassembly procedures prior to cleaning.
3. Remove bolt (if possible) and insert fitted cleaning rod bore guide in action.
4. Soak a patch in bore solvent (similar to Hoppes #9).
5. Center and affix the patch on the brass jag, inserting it into the chamber end of the barrel. A misaligned patch may cause the jag to damage the lands of the rifling, so make sure the patch is centered on the jag.
6. Run the patch the full length of the barrel, retracting it upon reaching the end of the muzzle.
7. Let the solvent sit for a minute.
8. Continue to run patches through the bore until carbon residue is minimized.
9. Run a dry patch through the bore to ensure carbon residue has been removed.
10. Soak a patch in copper solvent (Sweet’s or KG-12).
11. Run the patch through the bore, leaving it to sit for 3-5 minutes (do not let solvent sit for more than 15 minutes.*)
12. Repeat this process until no blue residue remains on the patches.
13. Run a patch of Hoppes #9 and a dry patch through the bore to neutralize the copper solvent.
14. Inspect the barrel prior to reassembling the rifle, verifying that no bore obstructions remain.

*Please note that some ammonia-based copper solvents may prove to be corrosive if left sitting in the barrel for an extended period of time. It is essential that these solvents be removed within 15 minutes to avoid ruining the bore.

The Chamber
Proper cleaning of the chamber is a critical component of a general cleaning procedure. Carbon rings can build up near the neck and throat of the chamber wall, leading to feeding malfunctions and pressure spikes inside the chamber.

The chamber can be the trickiest part of the barrel to effectively clean, due to its fluctuation in size and the awkward ergonomics often required to remove carbon residue. Numerous chamber specific devices have been created to address this problem, and while some should be avoided (steel chamber brushes), others can be used to great effect (cleaning stars and plastic dental picks). The simplest approach to cleaning a chamber is to apply solvent to a couple patches, and use the cleaning rod to spin the wadded up patches inside the confines of the chamber. This should aid in removing any excess carbon. A Q-Tip can be used to reach portions of the chamber unreached by patches.

The Barrel Exterior
While the condition of the crown, rifling, and chamber are essential to firearm performance, the finish of the exterior should also be cleaned after handling. Condensation, humidity, direct water contact, and salt residue from skin contact can cause rust or corrosion. An application of anti-corrosion products is recommended when placing a firearm into deep storage for an extended period of time. [Editor: AccurateShooter.com recommends Corrosion-X or Eezox, but other products work well too.]

Finding Cleaning Components
While most cleaning components can be found at your local gun shop, some specialty items may need to be sourced through online retailers such as Brownell’s. Criterion utilizes both Dewey and Pro-Shot brand cleaning components during our day-to-day operations.

Do you have any rifle cleaning tips or tricks not mentioned in the above article? We’d love to hear about them. You can post your comments below.

Permalink - Articles, Tech Tip 3 Comments »
January 22nd, 2016

Tips for Using LEE Collet Dies

For those who prefer to neck-size their brass (rather than full-length-size), the LEE Collet Die is a popular, inexpensive option. It works by having collet tangs or “fingers” press the neck against a central mandrel. The benefit is that you get a very straight neck, which is sized consistently from top to bottom. Canadian shooter Jerry Teo explains: “LEE Collet Dies produce sized cases with very low runout (measured runout is under .001″ using a Sinclair concentricity gauge). You also don’t get the build-up of brass at the base of the neck, as can happen with bushing neck dies. The neck-shoulder junction stays nice and crisp.”

LEE Precision Collet Die

TIP ONE — Adjusting Tension
LEE Collet dies don’t have a specific mechanical adjustment for neck tension. But you CAN easily modify the die to provide more or less tension. If you want to adjust the neck tension using a Lee Collet die, you can simply chuck the mandrel in a drill and reduce the diameter with some sand-paper (to increase neck tension) or you can order a mandrel the next caliber larger and turn it to whatever diameter you want (the larger the mandrel diameter, the less the neck tension). You can also order custom mandrels from Lee sized to any diameter you want.

TIP TWO — Polish and Tune for Easy Case Removal
Some users have complained that their Collet Dies grab the case-neck too firmly, making the case hard to remove. There are solutions to this problem. First inspect the collet fingers and smooth the inner surface up a bit with polishing compound or an extra-fine sanding pad. Second, you can open up the fingers a little bit. LEE recommends that if your Collet Die is sticking, take a steel punch and tap the fingers apart a little bit so that the natural “unloaded” position is wider. Lastly, you should lightly lubricate the outside of the collet fingers (see arrows) before you re-assemble the die. This will ensure they slide smoothly. Also, to prevent the collet fingers from closing too tight, never load up the die with your press without putting a case in place first. Without a case neck between the collet fingers and the mandrel, the collet can clamp itself too tight as you raise the ram.

TIP THREE — Size Twice and Spin Your Case 1/8th Turn
After reaching fully “down” on your press handle, withdraw the case about an inch and manually rotate it about 1/8th (NOT 1/4 or 1/2) turn while still in the shell-holder, then size again. This will place the die’s collet petals on the four “high spots” of the case neck and will result in a rounder, more evenly-sized neck with slightly more bullet tension. This takes only about one second more per case and is well worth the slight extra effort. (We thank reader Stonecreek for this smart tip).

Permalink Reloading, Tech Tip 15 Comments »
January 20th, 2016

Primer Seating Depth Uniformity and Accuracy

Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. Yesterday’s post covered primer seating depth. This article offers many useful tips — including a clever way to measure primer seating depth with ordinary jaw-type calipers. Visit the USAMU Facebook page next Wednesday for the next installment.

USAMU reloading tip

Primer Seating Depth — Why Uniformity is Important
The first concern is for safety: for that reason, primers should be seated below flush with the case head. One primary cause of “slam fires” (which includes catastrophic failures from firing out of battery) is “high,” or protruding primers. These stand above the case head, are readily felt with simple finger-tip inspection, and may fire when slammed by the bolt face and/or a floating firing pin in feeding.

Here at the USAMU, we ensure our rifle primers generally run -0.003″ to -0.005″ below the case head. Maximum primer depth is -0.006″ and minimum is -0.002″. Upon inspection, any cases with high primers will be corrected before loading. Aside from improving ballistic uniformity, ensuring the primers have proper compression upon seating also helps reduce possible misfires. These can be caused by the firing pin’s expending part of its energy either seating the primer or having to deform the primer cup enough to reach the anvil.

SMART TIP: How to Measure Primer Seating Depth with a Set of Calipers
A zeroed, precision set of standard calipers will also measure primer seating depth. (You don’t really need a custom tool.) Merely close the jaws and place the calipers’ narrow end squarely across the center of the case head/primer pocket. Keeping the narrow end in full contact with the case head, gently open the jaws, and the center bar will extend until it reaches the primer face. Voilà! Primer depth is read on the dial. Taking a few measurements to ensure accuracy and repeatability is recommended until one is familiar with this technique.

Brass and Primer Defects Can Cause Seating-Depth Variances
Factors affecting variance of primer seating depth include brass maker and lot number — all primer pockets are not created equal! Another factor is the primer manufacturer and individual primer lot. We’ve encountered occasional primer lots by top-quality makers that included some primers with slight defects affecting seating. While finely accurate, these primers were out-of-round or had small slivers of cup material protruding which affected primer feeding or seating depth.

Has one’s brass been fired previously? If so, how many times and the pressures involved also affect future primer seating. Obviously, this is another factor in favor of segregating one’s high-accuracy brass by maker, lot number, and number of times fired, if possible.

Measuring Primer Seating Depth with Purpose-Built Gauge
The next question, “How do we measure primer depth?” happily can be answered using tools already owned by most handloaders. [See tip above on how to measure depth with calipers.] At the USAMU, we have the luxury of purpose-built gauges made by the talented machinists of the Custom Firearms Shop. One places the primed case into the gauge, and the dial indicator reads the depth quickly and easily. The indicator is calibrated using a squarely-machined plug that simulates a case head with a perfectly flush-seated primer, easily giving meaningful “minus” or “plus” readings. The gauge is usable with a variety of case head sizes.

Primer Seating with Progressive Presses
Methods of primer seating include hand-seating using either hand held or bench-mounted tools, vs. progressive-press seating. Progressive presses may either seat by “feel,” subjective to each operator, or by using a mechanical “stop” that positively locates primers nearly identically every time. Testing here has shown that we get more uniform seating with the latter type progressive press, than we do with a high-quality bench-mounted tool lacking a positive stop.

Primer stop depth adjustments on our main progressive presses involve turning a punch screw in and out. While the screw is not calibrated, fine “tick” marks added to the top of the press help users gauge/repeat settings by “eye” efficiently with practice. Then, once a sample of primed cases is run to confirm the range and accuracy of depths, the identifying lot number and maker is noted on the press for reference. When it’s necessary to switch brass/primer lots, changes are easy to make and settings are easily repeated when it’s time to switch back.

Permalink Reloading, Tech Tip 2 Comments »
January 19th, 2016

Tech Tip: How to Print Better, More Durable Targets

Printing Targets card stock heavy paper benchrestMost of us have access to a printer at home or at work. That means you can print your own targets. You’ll find hundreds of free target designs online, including dozens of downloadable targets on our AccurateShooter.com Target Page. If you’re feeling creative, you can design your own target with a computer drawing program such as MS Paint.

Paper Stock Is Important
If you want your self-printed targets to show shots cleanly (and not rip when it gets windy), you should use quality paper stock. We recommend card stock — the kind of thick paper used for business cards. Card stock is available in both 65-lb and 110-lb weights in a variety of colors. We generally print black on white. But you might experiment with bright orange or yellow sheets. Forum Member ShootDots report: “They sell cardstock at Fed-Ex Kinko! I use either Orange or Yellow. That makes it easy to see the bullet holes clearly.” On some printers, with the heavier 110-lb card stock, you will need to have the paper exit through the rear for a straighter run.

Printing Targets card stock heavy paper benchrest

Here are some Target-Printing Tips from our Forum members:

“Staples sells a 67-lb heavy stock that I have settled on. I use the light grey or light blue, either of these are easy on the eyes on bright days. I have used the 110-lb card stock as well and it works fine. It’s just a little easier to print the lighter stuff.” (JBarnwell)

“Cardstock, as mentioned, works great for showing bullet holes as it doesn’t tear or rip like the thin, lightweight 20-lb paper. I’ve never had a problem with cardstock feeding in the printer, just don’t stick too many sheets in there. If I need three targets, I load only three card stock sheets”. (MEMilanuk)

“I’ve used Staples Sticker paper. This works well and no staples are required (joke intended). It helps if you put slight tension on the lighter weight paper when mounting it on the target frame.” (Mac 86951).

Printing Targets card stock heavy paper benchrest

Here are some tips for using lighter weight paper (if you want to save money or your printer won’t work with heavier stock):

“20-lb bond works pretty well for me if I use a spray adhesive and stick the entire back of the paper’s surface to the backer board.” (Lapua40X)

“I use the regular 20-lb paper but the only time it tears is when there is no backer to support it. This can be an issue when going to a public range and the backer are all shot out. I use a large construction paper backer that I clip onto the stands.” (CPorter)

Here Are Three of Our Favorite Targets. Click to Download PDFs.

FREE Accuracy Precision Rifle Shooting Target

FREE Accuracy Precision Rifle Shooting Target FREE Accuracy Precision Rifle Shooting Target
Permalink - Articles, Tech Tip 8 Comments »
January 15th, 2016

Build Your Own Concrete Shooting Bench

build your own concrete shooting bench

Who hasn’t dreamed of having a professional-quality, permanent shooting bench on their own property? Well here’s an article that can help you make that dream come true. This “how-to” feature from the archives of RifleShooter Magazine shows how to build a quality concrete shooting bench step-by-step.

build your own concrete shooting bench

All aspects of the construction process are illustrated and explained. The author, Keith Wood explains: “Construction happened in three phases — first creating the slab foundation, then the support pillars (legs), and finally the table.”

Click image below to load article with slide show.
build your own concrete shooting bench

Each step in the process is illustrated with a large photo and descriptive paragraph. Starting with framing the foundation (Step 1), the article illustrates and explains the 15 Steps that produce the finished, all-concrete bench (see top photo).

Permalink - Articles, Tech Tip 2 Comments »
January 10th, 2016

Chronograph Testing — Tips from the USAMU

USAMU Marksmanship Unit Velocity Chronograph Testing Sample Sizes

Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. This past week’s “Handloading Hump Day” article, the latest in a 7-part series, relates to chronograph testing and statistical samples. We highly recommend you read this article, which offers some important tips that can benefit any hand-loader. Visit the USAMU Facebook page next Wednesday for the next installment.

Chronograph Testing — Set-Up, Sample Sizes, and Velocity Factors

Initial Chronograph Setup
A chronograph is an instrument designed to measure bullet velocity. Typically, the bullet casts a shadow as it passes over two electronic sensors placed a given distance apart. The first screen is the “start” screen, and it triggers an internal, high-speed counter. As the bullet passes the second, or “stop” screen, the counter is stopped. Then, appropriate math of time vs. distance traveled reveals the bullet’s velocity. Most home chronographs use either 2- or 4-foot spacing between sensors. Longer spacing can add some accuracy to the system, but with high-quality chronographs, 4-foot spacing is certainly adequate.

Laboratory chronographs usually have six feet or more between sensors. Depending upon the make and model of ones chronograph, it should come with instructions on how far the “start” screen should be placed from one’s muzzle. Other details include adequate light (indoors or outdoors), light diffusers over the sensors as needed, and protecting the start screen from blast and debris such as shotgun wads, etc. When assembling a sky-screen system, the spacing between sensors must be extremely accurate to allow correct velocity readings.

Statistics: Group Sizes, Distances and Sample Sizes
How many groups should we fire, and how many shots per group? These questions are matters of judgment, to a degree. First, to best assess how ones ammunition will perform in competition, it should be test-fired at the actual distance for which it will be used. [That means] 600-yard or 1000-yard ammo should be tested at 600 and 1000 yards, respectively, if possible. It is possible to work up very accurate ammunition at 100 or 200 yards that does not perform well as ranges increase. Sometimes, a change in powder type can correct this and produce a load that really shines at longer range.

The number of shots fired per group should be realistic for the course of fire. That is, if one will be firing 10-shot strings in competition then final accuracy testing, at least, should involve 10-shot strings. These will reflect the rifles’ true capability. Knowing this will help the shooter better decide in competition whether a shot requires a sight adjustment, or if it merely struck within the normal accuracy radius of his rifle.

How many groups are needed for a valid test? Here, much depends on the precision with which one can gather the accuracy data. If shooting from a machine rest in good weather conditions, two or three 10-shot groups at full distance may be very adequate. If it’s windy, the rifle or ammunition are marginal, or the shooter is not confident in his ability to consistently fire every shot accurately, then a few more groups may give a better picture of the rifle’s true average.

Preliminary Load Development and Velocities
When developing a load for ones firearm, a chronograph is a very useful tool. Naturally, it tells the bullet speed, allowing ballistic calculations for wind deflection and trajectory, as well as velocity variation. It can also be used, in conjunction with recent handloading manuals, as an indirect indicator of pressure.

Differences between individual barrels, chamber throats, and powder lots, plus many other variables, can cause results to differ from those cited in the manuals. Thus, beware the notion of a “magical high-speed barrel.”

When Velocities Raise Pressure Concerns — Suppose the manual states that their 26-inch .260 barrel achieved 2900 fps with X bullet, Y powder, Z case, and W primer. If you achieve that speed with identical components in your 26-inch barrel while using five (5) grains less powder, that should raise a red flag. Pressures may be at or near maximum in your rifle, despite the higher “maximum” charge cited in the manual. Observe for pressure indicators as discussed in your manuals, and never exceed published maximum powder charges.

When working up a potential match load for your rifle, it is wise to survey at least 2-3 current factory sources of data for your powder/bullet combination. This will give you a sense of the variations possible due to random factors. Then, beginning at a safe, listed “starting” powder charge, work your way up in increasing powder increments while shooting over the chronograph. Also, assess your brass and rifle for signs of increasing pressure.

What size powder increments should be used? This depends on the case volume and powder chosen. A 0.3 grain or 0.5 grain increase in powder charge may be significant in a .223, but of little consequence in a .300 Magnum. Faster burning powders are more sensitive to small changes in powder charge, increasing pressures more rapidly than slow-burning powders.

Chronograph Sample Sizes — Factors to Consider
How many shots should one fire to obtain an accurate velocity for each powder charge increment when loading? That depends in part on the uniformity of velocities given by your particular powder/bullet/barrel combination.

For example: a 3- or 5-shot sample gives an extreme spread (ES) of 140 fps between the high and low velocities recorded. The lack of uniformity indicates that firing 1 or 2 shots over the chronograph to check a powder charge is likely to give a wide margin of error. In such a case, larger sample sizes will give a better idea of the true, average velocity. While approaching the loading manual’s listed maximum charge, track the ascending velocities per charge increment. One may well see that as charges approach maximum, velocities may become much more uniform. Moreover, velocity gains per increment of increase often become smaller. Ideally, one won’t encounter velocity variations this large. Changing primers and/or neck tension may increase uniformity. If wide variations persist, however, a different powder may offer great improvement.

Consider this: A 2-shot scan gives double the data of a one-shot sample. A 4-shot sample gives twice the data of a 2-shot scan. Larger samples are particularly useful if there is much velocity variation in the population.

On the other hand, one might already be familiar with a particular powder/bullet combination in one’s barrel. If it is known to have little variation, a 1 or 2-shot scan in the early stages while working up toward the maximum can be useful, while saving expensive bullets. As powder charges approach their maximum, some like to test accuracy while shooting over the chronograph. Although it’s a bit trickier to set up the bench, chronograph and target, this does yield more data per bullets expended. In such an instance, 5-shot or even 10-shot groups may be desirable at times.

Consider 20-Shot Sample for Long-Range Match Loads
Once one arrives at a load combination intended for competition use, one should chronograph at least a 10-shot sample. This gives a reasonable picture both of the load’s uniformity and its average velocity. For long range use, a 20-shot sample of ones finalized match load is even better. This accurately shows the uniformity of one’s velocities over time. It is more likely to reveal any rare shots that develop velocities significantly different from the average.

Thus ends Part 7 in our series on Accuracy Testing and Chronographing. Next week, we’ll conclude our section on Chronograph Testing. Until then, stay safe and enjoy the shooting sports!

Permalink Reloading, Tech Tip No Comments »
January 3rd, 2016

Download FREE Target Centers for 300-Yard Practice

F-Class Target center NRA

Here’s a handy training option for F-Class shooters. Forum member SleepyGator is an F-Class competitor, but it’s not convenient for him to shoot at long ranges close to home. Accordingly, he wanted some “reduced-distance” targets he could use at 300 yards for practice. There is an official reduced-distanced standard for 300-yard F-Class matches. This utilizes the NRA No. MR-63FC – F-Class Target Center which is pasted over the MR-63 target. It provides a 1.42″ X-Ring, 2.85″ 10-Ring, and 5.85″ Nine-Ring. (The dimensions of F-Class targets are found in the NRA High Power Rules, Sec. 22, part 4, page 70 — see sample below.)

F-Class Reduced Target Centers

CLICK HERE to Download F-Class 300-yard Target Centers (.Zip archive with three targets)

To duplicate the 300-yard target, SleepyGator has prepared a printable version of the MR-63FC Target Center, along with a pair of training targets with two bulls and five bulls. The two-bull and five-bull targets mirror the scoring rings on the MR-63FC, but they display only the innermost three rings and two rings respectively. All three targets are Adobe Acrobat (PDF) files that can be easily printed. You may need to adjust the scale (sizing) on your printer to get the dimensions exactly correct. As noted above, when printed, the 10-Ring on all three targets should measure 2.85″. This should provide some handy practice targets you can use between matches. Thanks to SleepyGator for providing these targets. You can download all three as a .Zip archive. After downloading the .Zip file, just click on the .Zip archive to extract the individual targets.

CLICK HERE to Download NRA High Power Rules with F-Class Target Dimensions

F-Class Target Paste Center

Permalink Competition, Tech Tip 1 Comment »
December 29th, 2015

Find and Download MIL-STD Spec Sheets for FREE

Looking for authentic U.S. Military Specification Standards (MIL-STD) for gun parts, safety products, or other hardware? Log on to EverySpec.com. This website provides FREE access to the complete archive of U.S. Government spec sheets and technical manuals. You can quickly access and download thousands of public domain U.S. Government documents. For example, we searched for “Picatinny” and came up with MIL-STD-1913 “Dimensioning of Accessory Mounting Rail for Small Arms Weapons”. With one click we downloaded the file as a PDF. Then a search for “M118″ yielded the engineering drawing for 7.62×51 M118 LR Match ammo. Pretty cool.

Using EverySpec.com is fast and easy. And everything you find and save is FREE. Search as often as you like — there are no limits on search requests or downloads. You can either search by keyword, or Federal Supply Class Code (FSC). CLICK HERE for a complete list of FSCs for all products.

Here are FSCs for a few common product types. Keep in mind that there are hundreds of other FSCs — for everything from Office Supplies (FSC 7510) to Nuclear Projectiles (FSC 1110).

1095 — Miscellaneous Weapons (incl. Knives)
1240 — Optical Sighting and Ranging Equipment
1395 — Miscellaneous Ammunition (incl. Small Arms)
3455 — Cutting Tools for Machine Tools
6140 — Batteries, Rechargeable
6230 — Electric Portable Lighting Equipment
7640 — Maps, Atlases, Charts and Globes
8340 — Tents and Tarpaulins
8405 — Outerwear, Mens

Credit Gunsmith Thomas ‘Speedy’ Gonzales for finding this resource. Thanks Speedy!
Permalink Bullets, Brass, Ammo, Tech Tip 1 Comment »
December 28th, 2015

Flash-Hole Fix — Clearing Flash-Hole Obstructions in Your Brass

Flash-hole reamer

Even with high-quality brass from Lapua, Norma, and RWS, occasionally you may find one or two cases per box which have a small flake or obstruction in the flash-hole. This will appear like a thin crescent on one side of the flash hole (see photo). You should inspect ALL new brass before loading to identify any pieces with a partially-obstructed flash hole. It’s a good idea to remove any flake or thin crescent left as an artifact of the flash-hole forming process. Because the flash-hole itself is normally centered and of the correct diameter, it is not necessary to ream the flash-hole to a larger diameter. All you really need to do is remove the small obstruction(s). This can be done quickly with inexpensive tools.

Use a Small Pin Vise to Remove Flash-Hole Obstructions
Folks have asked if there is a tool that can remove obstructions from a Lapua small, BR-sized flash hole without opening the hole size. The Lapua PPC/BR flash hole is spec’d at 1.5mm, which works out to 0.059055″. Most of the PPC/BR flash-hole uniforming tools on the market use a 1/16″ bit which is nominally 0.0625″, but these often run oversize — up to 0.066″.

If you want to just clear out any obstructions in the flash hole, without increasing the flash hole diameter, you can use an inexpensive “pin vise” with an appropriate drill bit. For $1.00, eHobbyTools.com sells a 1.5mm drill bit, item 79186, that matches the Lapua flash hole exactly. Other vendors offer a #53 pin vise drill bit that measures .0595″ or .060″ (depending or source). An 0.0595″ bit is close enough. You can find pin vises and these small-diameter drill bits at hobby stores.

Pin vises Lapua Flash hole

For quite some time, Sinclair Int’l has sold a similar device for small (PPC and BR-size) flash holes. Like the 07-3081 unit for large flash holes, the 073000 Reamer for small flash holes works from the outside, so it can index off the primer pocket. It reams to .0625″, and also costs $39.99. The standard dimension for Lapua 220 Russian and 6mmBR flash holes is 1.5mm or .0590″. This tool will permit standard-size decapping rods with .0625″ tips to work without binding. However, note that both Forster and Redding normally supply .057″ decapping pins with their PPC and BR dies. So, it is NOT necessary to ream your Lapua BR/PPC flashholes, unless you prefer to do so for uniformity. It IS, however, a good idea to check BR/PPC flash holes for burrs before loading the first time.

AccurateShooter Sinclair Flash Hole Reamer

NOTE: If you purchase either the 073081 or 073000 Sinclair Flash Hole Reamer tools, we recommend you mic the cutter tip before you process a bunch of cases. Sometimes a tip comes through that is oversize. This will ream the flash holes larger than you may intend.

Permalink Reloading, Tech Tip 2 Comments »
December 26th, 2015

Doh! Make Sure Your Ammo Fits Your Chamber!

Ruptured Cartridge Case

If you don’t match your ammo to your chamber, bad things can happen, that’s for sure. A while back, Forum member BigBlack had an experience at the gun range that reminds us of the importance of safety when shooting. He encountered evidence that someone had fired the wrong cartridge in a 7mm WSM rifle. The problem is more common than you may think. This Editor has personally seen novices try to shoot 9mm ammo in 40sw pistols. BigBlack’s story is along those lines, though the results were much more dramatic. It’s too bad a knowledgeable shooter was not nearby to “intervene” before this fellow chambered the wrong ammo.

7mm-08 is Not the Same as a 7mm WSM
BigBlack writes: “I know this has probably been replayed a thousand times but I feel we can never be reminded enough about safety. This weekend at the range I found a ruptured case on the ground. My immediate thoughts were that it was a hot load, but the neck area was begging for me to take a closer look, so I did. I took home the exploded case and rummaged through my old cases until I found a close match. From my investigative work it appears someone shot a 7mm-08 in a 7mm WSM. Take a look. In the above photo I’ve put together a 7mm WSM case (top), the ruptured case (middle), and a 7mm-08 case (bottom).”

The photo reveals what probably happened to the 7mm-08 case. The shoulder moved forward to match the 7mm WSM profile. The sidewalls of the case expanded outward in the much larger 7mm WSM chamber until they lacked the strength to contain the charge, and then the case sides ruptured catastrophically. A blow-out of this kind can be very dangerous, as the expanding gasses may not be completely contained within the action.

Permalink Reloading, Tech Tip 2 Comments »
December 25th, 2015

Shooting Science: The Coriolis Effect Explained

Whittington Coriolis Effect
The Coriolis Effect comes into play with extreme long-range shots like this. The rotation of the earth actually moves the target a small distance (in space) during the course of the bullet’s flight. Photo by Dustin Ellermann at Whittington Center Range.

Coriolis Effect Bryan Litz Applied BallisticsWhen you’re out at the range, the Earth seems very stable. But it is actually a big sphere zooming through space while spinning around its axis, one complete turn every 24 hours. The rotation of the earth can create problems for extreme long-range shooters. During extended bullet flight times, the rotation of the planet causes an apparent deflection of the bullet path over very long distances. This is the ballistics manifestation of the Coriolis Effect.

Bryan Litz of Applied Ballistics has produced a short video that explains the Coriolis Effect. Bryan notes that Coriolis is “a very subtle effect. People like to make more of it than it is because it seems mysterious.” In most common shooting situations inside 1K, Coriolis is not important. At 1000 yards, the Effect represents less than one click (for most cartridge types). Even well past 1000 yards, in windy conditions, the Coriolis Effect may well be “lost in the noise”. But in very calm conditions, when shooting at extreme ranges, Bryan says you can benefit from adjusting your ballistics solution for Coriolis.

Bryan explains: “The Coriolis Effect… has to do with the spin of the earth. You are basically shooting from one point to another on a rotating sphere, in an inertial reference frame. The consequence of that is that, if the flight time of the bullet gets significantly long, the bullet can have an apparent drift from its intended target. The amount [of apparent drift] is very small — it depends on your latitude and azimuth of fire on the planet.”

Coriolis Effect Bryan Litz Applied Ballistics

Coriolis is a very subtle effect. With typical bullet BCs and velocities, you must get to at least 1000 yards before Coriolis amounts to even one click. Accordingly, Bryan advises: “Coriolis Effect is NOT something to think about on moving targets, it is NOT something to think about in high, uncertain wind environments because there are variables that are dominating your uncertainty picture, and the Coriolis will distract you more than the correction is worth.”

“Where you could think about Coriolis, and have it be a major impact on your hit percentage, is if you are shooting at extended range, at relatively small targets, in low-wind conditions. Where you know your muzzle velocity and BC very well, [and there are] pristine conditions, that’s where you’re going to see Coriolis creep in. You’ll receive more refinement and accuracy in your ballistics solutions if you account for Coriolis on those types of shots. But in most practical long-range shooting situations, Coriolis is NOT important. What IS important is to understand is when you should think about it and when you shouldn’t, i.e. when applying it will matter and when it won’t.”

The Coriolis Effect — General Physics
The Coriolis Effect is the apparent deflection of moving objects when the motion is described relative to a rotating reference frame. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object’s speed in the rotating frame.

A commonly encountered rotating reference frame is the Earth. The Coriolis effect is caused by the rotation of the Earth and the inertia of the mass experiencing the effect. Because the Earth completes only one rotation per day, the Coriolis force is quite small, and its effects generally become noticeable only for motions occurring over large distances and long periods of time. This force causes moving objects on the surface of the Earth to be deflected to the right (with respect to the direction of travel) in the Northern Hemisphere and to the left in the Southern Hemisphere. The horizontal deflection effect is greater near the poles and smallest at the equator, since the rate of change in the diameter of the circles of latitude when travelling north or south, increases the closer the object is to the poles. (Source: Wikipedia)

Permalink Shooting Skills, Tech Tip 5 Comments »
December 24th, 2015

Tuning Barrels for Enhanced Precision and Accuracy

Anschutz Tuner

When a shot is fired through it, a barrel will exhibit harmonics. Tuning these harmonics (the “waves” that propagate through the barrel) can alter point of impact and, if you’re lucky, reduce group size. Barrel tuners have been used successfully in rimfire benchrest for many years (see photo above). While there are competing theories as to how and why barrel tuners work on rimfire rifles, there is no question that the accuracy of some rimfire barrels can be improved with the addition of a tuner. By changing the position of weights at the end of the barrel, we’ve seen shooters shrink their average group size as well as adjust the “sweet spot” for different lots of rimfire ammo. On the other hand, tuners can be the source of great frustration; some installations may yield little or no benefit. A shooter may have to experiment with a variety of different tuner designs (and weights) to find the optimal configuration.

Gene Bukys Barrel Tuner 333smittyCenterfire Tuners–Still a Work in Progress
In centerfire benchrest competition, the vast majority of competitors do not use tuners, though a few short-range shooters such as Gene Bukys and Jackie Schmidt have enjoyed considerable success. Gene has won major championships with tuned rifles. In 2011 Gene won both the Super Shoot and World Benchrest Championship (WBC), and Gene recently set a new NBRSA Sporter Class Grand Agg Record.

Centerfire benchrest guns typically employ shorter barrels with a much fatter contour (larger diameter) than rimfire rifles. Because centerfire rounds produce much higher pressures and velocities that a 22LR, a centerfire barrel also exhibits much different vibration characteristics than a typical rimfire barrel. Nonetheless, there are pioneers working with centerfire tuners who believe that tuning may be the “next leap forward” in centerfire accuracy.

Shown below is a switch-barrel benchrest rifle built by Forum member Eddie W. of Texas. It features a dual-port Hall “M” action with a ShadeTree Engineering Tuner crafted by Butch Lambert. The gun is designed to take both a 6PPC barrel for group shooting and a 30BR barrel for score shooting. The gun was barreled by Wayne Shaw, and Eddie did the stock work himself. Eddie reports: “It is a very accurate rifle.”

Lambert Tuner

Will we see more tuners on centerfire rifles? Only time will tell. Some folks believe that, since one can easily adjust the loads shot by centerfire guns (by tinkering with the powder charge and seating depth), tuners have limited utility. On the other hand, tuner advocates such as Gene Beggs believe tuners can help keep your group sizes small even as conditions (temperature, humidity) change. Gene believes that, with an appropriate tuner, you can spend less time fiddling with the load specs (changing your powder charge) and instead “dial in” your sweet spot using the tuner.

Lambert Tuner

Permalink Gunsmithing, Tech Tip No Comments »
December 17th, 2015

Shoot BR Cases from Your PPC Action with Rebated Rims

Butch Lambert of ShadeTree Engineering provided this tip. Butch notes that many 6 PPC benchrest group shooters also enjoy shooting in score matches. But to be really competitive in the BR for score game, that means shooting a 30BR, which has a wider, .308-class rim (0.4728″ diameter). Likewise, if you want to compete in 600-yard registered BR events or in varmint matches, you probably want to run a bigger case, such as the 6BR, 6mm Dasher, or 6-6.5×47. Those cartridges also have the larger 0.4728″ rims.

To convert a PPC-boltface action to shoot the bigger cases you can spend a ton of money and buy a new bolt. That can cost hundreds of dollars. The simpler solution is to turn down the diameter of the larger cases on a lathe. Butch explains: “We’ve seen plenty of interest in rebating case rims. This lets you shoot a 30BR in score matches using your PPC action. All you need is a new barrel. This saves buying another bolt, receiver, or rifle if you have a PPC boltface. Anyone who has access to a lathe can do this job pretty easily. Yesterday I turned 150 case in about an hour.” Below are photos of a rebated 6BR case, along with the lathe form tool Butch uses to rebate the case rims.

Cutting Head for Rebating Rims

Permalink Gunsmithing, Tech Tip 6 Comments »
December 14th, 2015

Check Out 120+ FREE Technical Articles

Accurateshooter.com technical articles

AccurateShooter.comReaders who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into mutiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 120 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.

pillar Bedding

Stress-Free Pillar Bedding. Richard Franklin explains how to do a top-quality bedding job, start to finish.

On Target Software Review

OnTarget Software Review. Our Editors test free software that measures shot groups with great precision. We explain how to use the program and configure advanced features.

Savage Action Tuning Torque Settings

Savage Action Tuning. Top F-TR shooter Stan Pate explains how to enhance the performance of your Savage rifle by optimizing the torque settings of the action screws.

Precision Case Prep for Reloading

Complete Precision Case Prep. Jake Gottfredson covers the complete case prep process, including brass weight sorting, case trimming, primer pocket uniforming, neck-sizing, and, case-neck turning.

rifle stock painting and spraying

Stock Painting Instructions. Step-by-step guide for stock painting by expert Mike Ricklefs. Mike shows both simple coverage and fancy effects.

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December 14th, 2015

Winchester XPR Rifle Safety Notice and Recall

Winchester XPR Rifle Recall Safety

Winchester Repeating Arms has issued a Safety Notice and Recall for Winchester XPR rifles. This large-scale recall covers all XPR rifles, of all calibers. The issue involves the possibility of an unintentional discharge when the safety is manipulated. According to Winchester, continuous product testing revealed that moving the safety switch on the XPR rifle “may cause movement in the trigger system that could result in unintended firing of certain XPR rifles”. Accordingly, Winchester will replace certain trigger group parts in Winchester XPR rifles at no charge to the customer. Winchester requests that all owners of XPR rifles send their rifles back to the factory for retro-fitting.

For more details on how to return your rifle for retro-fitting, or if you are unsure if your rifle is included in the recall, or if you have any other questions, call 1-800-727-4312 or e-mail Winchester at XPR@winchesterguns.com. You can also CLICK HERE to view the Recall Notice and do a Serial Number search to verify your recall status. (By the terms of the notice, it appears that ALL XPRs are subject to the recall).

WARNING: Do not load or shoot any XPR rifle until it has been returned to the Winchester Service center and Received a retrofit. Failure to follow this warning may result in a risk of harm, including serious personal injury or death to you and others.

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