March 24th, 2017

Verify Your TRUE Scope Click Values with Tall Target Test

Scope Click Verify Elevation Tall Target Bryan Litz NSSF test turret MOA MIL

Have you recently purchased a new scope? Then you should verify the actual click value of the turrets before you use the optic in competition (or on a long-range hunt). While a scope may have listed click values of 1/4-MOA, 1/8-MOA or 0.1 Mils, the reality may be slightly different. Many scopes have actual click values that are slightly higher or lower than the value claimed by the manufacturer. The small variance adds up when you click through a wide range of elevation.

In this video, Bryan Litz of Applied Ballistics shows how to verify your true click values using a “Tall Target Test”. The idea is to start at the bottom end of a vertical line, and then click up 30 MOA or so. Multiply the number of clicked MOA by 1.047 to get the claimed value in inches. For example, at 100 yards, 30 MOA is exactly 31.41 inches. Then measure the difference in your actual point of impact. If, for example, your point of impact is 33 inches, then you are getting more than the stated MOA with each click (assuming the target is positioned at exactly 100 yards).

Scope Click Verify Elevation Tall Target Bryan Litz NSSF test turret MOA MIL

How to Perform the Tall Target Test
The objective of the tall target test is to insure that your scope is giving you the proper amount of adjustment. For example, when you dial 30 MOA, are you really getting 30 MOA, or are you getting 28.5 or 31.2 MOA? The only way to be sure is to verify, don’t take it for granted! Knowing your scopes true click values insures that you can accurately apply a ballistic solution. In fact, many perceived inaccuracies of long range ballistics solutions are actually caused by the scopes not applying the intended adjustment. In order to verify your scope’s true movement and calculate a correction factor, follow the steps in the Tall Target Worksheet. This worksheet takes you thru the ‘calibration process’ including measuring true range to target and actual POI shift for a given scope adjustment. The goal is to calculate a correction factor that you can apply to a ballistic solution which accounts for the tracking error of your scope. For example, if you find your scope moves 7% more than it should, then you have to apply 7% less than the ballistic solution calls for to hit your target.


CLICK HERE to DOWNLOAD Tall Target Worksheet (PDF)

NOTE: When doing this test, don’t go for the maximum possible elevation. You don’t want to max out the elevation knob, running it to the top stop. Bryan Litz explains: “It’s good to avoid the extremes of adjustment when doing the tall target test.I don’t know how much different the clicks would be at the edges, but they’re not the same.”

Should You Perform a WIDE Target Test Too?
What about testing your windage clicks the same way, with a WIDE target test? Bryan Litz says that’s not really necessary: “The wide target test isn’t as important for a couple reasons. First, you typically don’t dial nearly as much wind as you do elevation. Second, your dialed windage is a guess to begin with; a moving average that’s different for every shot. Whereas you stand to gain a lot by nailing vertical down to the click, the same is not true of windage. If there’s a 5% error in your scope’s windage tracking, you’d never know it.”

Scope Tall Test level calibrationVerifying Scope Level With Tall Target Test
Bryan says: “While setting up your Tall Target Test, you should also verify that your scope level is mounted and aligned properly. This is critical to insuring that you’ll have a long range horizontal zero when you dial on a bunch of elevation for long range shots. This is a requirement for all kinds of long range shooting. Without a properly-mounted scope level (verified on a Tall Target), you really can’t guarantee your horizontal zero at long range.”

NOTE: For ‘known-distance’ competition, this is the only mandatory part of the tall target test, since slight variations in elevation click-values are not that important once you’re centered “on target” at a known distance.

Permalink Optics, Tech Tip No Comments »
March 22nd, 2017

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.

(more…)

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March 22nd, 2017

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).

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March 20th, 2017

Cheap Tricks — Ten Handy Budget Items For Hand-Loaders

Budget reloading items

Useful reloading gear does not have to be costly. Here are ten handy (and very inexpensive) items that belong on your loading bench or in your range kit.

magnifying glassMagnifying Glass – We use a flat, 2″x2″ pocket 4x-8x magnifier. This folds up on itself. Very handy, we use it to inspect bullets and brass. Use this to check your flash holes for burrs, and check the meplats of your bullets before loading.

Clear 35mm Film Cannister – Use this to transfer the thrown powder charge to the little measuring cup that sits on your scale. That way you don’t get any kernel splash. Also if the charge weight is obviously off, it’s easy to dump back in the measure. A film canister works pretty well as a trickler too.

Compressed Air in a Can -- Get these at office supply stores. Use the can (with tube attached) to blow crud out of cases after cleaning the neck with a brush, and blast loose debris out of primer pockets.

Pin Vise – A simple $7.00 pin vise with a #53 bit is perfect for deburring Lapua PPC and BR flash holes without reaming the flash-holes any larger. The Lapua PPC/BR flash-hole diameter is 1.5 mm, or 0.059″. eHobbyTools.com sells a 1.5mm pin vise bit. Other vendors offer a #53 pin vise bit that measures .0595″ or .060″ (depending or source). You can find pin vises and bits at hobby stores.

Bounce Dryer Sheets – The common dryer sheets eliminate “static cling” on your plastic reloading parts such as powder measure cylinders, powder funnels, and reloading press plastic bins. Thanks to Doc76251 for this tip.

BallistolBallistol Aerosol – Try using this versatile lubricant/solvent for full-length sizing. Spray some on a patch and you can wipe the carbon of your case necks. Then, continue to apply a very small amount of Ballistol on the case bodies — just thin sheen is all you need. Ballistol is super slippery, and easy to remove. For general full-length sizing (on small cases) it works great and doesn’t leave a gooey, waxy, or chalky residue. For heavier case-forming jobs, we recommend Imperial Die Wax.

Shotgun Mop – Stick this in the chamber when using Wipe-Out foaming bore cleaner. This will seal off the chamber so the foam doesn’t flow into your action. For long chambers screw on one section of cleaning rod to aid extraction.

Colored Sharpie Marking Pens – Mark your bullets ahead of the bearing surface, and the color transfers to the target. This way you can shoot multiple loads at the same point of aim and discern which load shoots the tightest. (Recommended for 300 yards and beyond). With colored bullet tips you can test multiple loads “round robin” to equalize wind effects. When testing seating depths for example, you can mark the longer-seated set of bullets red and the shorter-seated set green and shoot them during the same sequence. Just look at the colored marks on the target to see which grouped better.

Sharpies Pens

Thin Latex Gloves – You should keep a box of inexpensive, disposable latex gloves (the kind doctors use) in your loading room. These will prevent contamination of primers or powder kernels that you handle directly. Also, use the gloves when handling fine blued tools or firearms to prevent transfering body oils and salts that promote rust.

Plastic Washers for Neck Mic – If you use a Sinclair Neck-wall Micrometer Gauge with integral stand, you can use thin plastic washers to adjust the height of the case on the mandrel. This makes it much easier to measure the same point on the case neck every time. Thanks to MikeCR for this tip (and photo).

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March 15th, 2017

Harris Bipod Adapter for Flat-Bottomed Stocks

Harris #9 hb9 flat-bottom flat foreend stock adapter accurateshooter.com

Harris #9 hb9 flat-bottom flat foreend stock adapter accurateshooter.comFlat-bottomed stocks are great for benchrest shooting, but their geometry is not ideal for mounting conventional Harris bipods, which were originally designed for stocks with a curved underbelly. Long-time Forum member Mark S. wanted to know if there is a way to make a stud-mounted bipod more secure on a flat-bottomed stock: “I have started shooting some steel matches that require shooting from bipods. My best gun for the job is a 6BRX in a MBR benchrest stock. I have installed a stud, but the bipod is still wanting to turn sometimes. What do you use?”

Here’s a solution for Mark and others using Harris bipods on flat-bottomed stocks with studs. Get the Harris-made #9 (HB9) adapter. Costing just $22.12 (at Midsouth), the HB9 adapter provides an extended contact surface with pads, so the bipod will fit securely on your flat fore-end.The HB9 adapter also has a center cut-out for the swivel stud so the bipod adapter aligns properly on the underside of your stock:

Midsouth Shooters Supply sells the Harris #9 (HB9) flat-bottom stock adapter for $21.26, part number 053-9. CLICK HERE to order.

Permalink Gear Review, Tech Tip 4 Comments »
March 12th, 2017

Monitor Barrel Heat with Handy Temp Strips

Barrel Heat Temp Temperature gauge strip McMaster Carr

You never want your barrel to get too hot. Accuracy suffers when barrels over-heat, and excessive heat is not good for barrel life. So how do you monitor your barrel’s temperature? You can check if the barrel is “warm to the touch” — but that method is not particularly precise. There is a better way — using temperature-sensitive strips. McMaster.com (an industrial supply house) offers stick-on temp strips with values from 86° F to 140° F. A pack of ten (10) of these strips (item 59535K13) costs $12.16 — so figure it’ll cost you about $1.20 per barrel for strips. That’s cheap insurance for your precious barrels. For best barrel life, try to stay under 120 degrees F.

Barrel Heat Temp Temperature gauge strip McMaster Carr

Forum member Nomad47 says: “I have temperature strips (bought at McMaster-Carr) on all my barrels. I try not to shoot when the barrel gets to 122 degrees or higher[.]” Here are photos of the McMaster-Carr temp strips on Nomad47’s customized Savage.

Barrel Heat Temp Temperature gauge strip McMaster Carr

Bad things can happen if your barrel gets too hot. First, with some barrels, the point of impact (POI) will shift or “walk” as the barrel heats up excessively. Second, even if the POI doesn’t change, the groups can open up dramatically when the barrel gets too hot. Third, if the barrel is very hot, the chamber will transfer heat to your loaded cartridge, which can lead to pressure issues. Finally, there’s considerable evidence that hot barrels wear out faster. This is a very real concern, particularly for varmint shooters who may shoot hundreds of rounds in a day. For this reason, many varminters switch among various guns, never letting a particular barrel get too hot.

Neconos.com offers Bar-L Benchrest strips that visually display heat readings from 86 to 140 degrees. Think of these strips as compact, unbreakable thermometers. With adhesive backing, they can also be used to monitor barrel heating. Put a strip on the side of the barrel and the barrel’s temp will be indicated by a stripe that changes from black to green. There is also a “general purpose” strip that reads to 196 degrees (bottom row). The Benchrest strip (86F to 140F) is in the middle. Bar-L temp strips cost $9.00, or $25.00 for a 3-pack.

Permalink Gear Review, Tech Tip 2 Comments »
March 11th, 2017

Get FREE SAAMI Rimfire Cartridge and Chamber Diagrams

SAAMI Cartridge Diagrams

Planning a rimfire build in the future, or want to get the exact specifications for your 17 Mach 2, 17 HMR, 17 WSM, .22 LR, or .22 WMR rifle? Then we’ve got you covered. CLICK HERE to download an official SAAMI document with specs for all popular rimfire ammunition. This FREE 89-page PDF includes complete Cartridge and Chamber drawings and headspace specifications. The document even includes info on pressure terminology, headspace gauges, and test barrels.

DOWNLOAD SAAMI Rimfire Cartridge/Chamber Drawings >>

SAAMI, the Sporting Arms and Ammunition Manufacturers’ Institute, is an association of the nation’s leading manufacturers of firearms, ammunition and components. Founded in 1926, SAAMI promulgates industry standards for firearms ammunition safety, interchangeability, reliability and quality.

SAAMI offers diagrams for ALL popular, modern rimfire cartridges:

SAAMI Cartridge Diagrams

Here’s the Official SAAMI Drawing for the 17 HMR Cartridge:

SAAMI Cartridge Diagrams

SAAMI Website Also Offers Centerfire Cartridge and Shotshell Diagrams
From the SAAMI website you can also access hundreds of FREE official cartridge diagrams and chamber drawings for all centerfire ammo types and Shotshells. Simply click on the Cartridge and Chamber Drawings link and then choose your ammo type: Pistol and Revolver, Rifle, or Shotshell.

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip No Comments »
March 10th, 2017

Black Rifle Maintenance — AR15 Cleaning How-To Videos

Barrel cleaning AR15 bolt carrier carbon Jerry Miculek gas key direct impingement

Let’s face it, AR-platform rifles run dirty, at least compared to typical bolt-action rifles. The AR15 works by piping gas from the barrel back into the bolt carrier, causing the bolt to unlock and the carrier to move the bolt backward. The “exhaust gas” from the barrel contains soot and carbon. The carbon will form hard deposits on the bolt. In addition, the carbon can combine with lube on the bolt carrier to make a nasty, paste-like sludge. This can be particularly problematic when the black paste pollutes the ejector and extractor recess.

This Editor has inspected dozens of ARs over the years. Other than mag-related malfunctions, the most common cause of AR cycling problems I found was oily gunk in the extractor and ejector areas. Many AR owners overlook these critical areas. Look at an AR that hasn’t been cleaned properly and you’ll probably find black gunk (and small brass shavings) in the ejector and extractor recesses.

If you want to keep your black rifle running smoothly and reliably, you must clean it regularly and follow the correct maintenance procedures. Here are three videos that explain how to properly disassemble and clean AR-platform rifles.

Take-Down and Full Cleaning of AR15 by Jerry Miculek

Here ace shooter Jerry Miculek takes down and cleans an AR-platform rifle belonging to his daughter Lena. This is a good video because Lena’s rifle was “run hard and packed up dirty” so you can see where carbon and grease build up. This 35-minute video is very thorough. Jerry is one of the nation’s top action carbine shooters, so listen carefully to his advice on cleaning and lubrication.

How to Clean Your AR-Platform Rifle

This is a good basic video that shows the take-down and cleaning procedure for a typical AR15. It uses some fast-motion sequences to speed up the story. Check out this video if you don’t have the time to sit through the Miculek video above.

Cleaning and Lubricating AR15 Bolt Carrier Group

This video offers very specific advice on the bolt carrier group, which receives the dirty gas directly from the barrel. Be sure to check the extractor and ejector recesses. That’s where old lube, brass shavings, and carbon accumulate. Follow the directions in this video for lubrication, and don’t over-lubricate the bolt carrier — that will only capture more carbon.

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March 7th, 2017

.338 Lapua Magnum Barrel Cut-Down Velocity Test

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com
Shooters contemplating purchase of a .338 LM rifle often ask: “What length barrel should I get?” Rifleshooter.com recently performed a test that provides interesting answers…

Our friends at RifleShooter.com like to slice and dice — barrels that is. They have done barrel length cut-down tests for popular calibers like the .223 Rem, 6.5 Creedmoor, and .308 Winchester. But now they’ve tackled something way bigger — the .338 Lapua Magnum, a true “Big Boomer”. Starting with a beefy 30″-long Pac-Nor Barrel, RifleShooter.com chopped the tube down in one-inch increments all the way down to 17 inches (that’s 14 different lengths). At each new (shorter) barrel length, velocity was measured with a MagnetoSpeed chronograph using two different loads, 250gr SMKs with H4831sc and 300gr SMKs with Retumbo. Four shots were fired at each length with each load, a total of 112 rounds.

Load #1: 250gr Sierra MK, Lapua brass, CCI #250 primer, H4831SC, OAL 3.720″.
Load #2: 300gr Sierra MK, Lapua brass, Win WLRM primer, Retumbo, OAL 3.720″.

READ FULL .338 Lapua Magnum Barrel Cut-down Velocity TEST >>

The .338 Lapua Magnum is a jumbo-sized cartridge, that’s for sure…
.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

Donor Barrel Sacrificed for Science
Rifleshooter.com’s Editor explains: “Brandon from Precision Addiction offered to send us his .338 barrel for our .338 Lapua Mag test. I took him up on his offer and he sent me his used Pac-Nor chrome-moly barrel with about 600 rounds though it. This thing was a beast! A heavy 1.350″ shank that ran straight for 6″, until tapering to 1″ at 30″ in length.”

.338 Lapua Magnum LM barrel length vs velocity cut down test chrono rifleshooter.com

Results Summary

.338 Lapua Magnum with 250gr Sierra MatchKings
After shortening the barrel from 30″ to 17″, total velocity reduction for the 250-grainers was 395 FPS, an average loss of 30.4 FPS per 1″ cut. The amount of velocity loss per inch rose as the barrel got shorter, with the biggest speed reduction, a loss of 55 FPS, coming with the cut from 18″ to 17″.

Start Velocity: 2942 FPS | End Velocity: 2547 FPS | Average Loss Per Inch: 30.4 FPS

.338 Lapua Magnum with 300gr Sierra MatchKings
Shooting the 300-grainers, total velocity reduction was 341 fps, an average of 26.2 FPS loss per 1″ cut (30″ down to 17″). However, the speed actually increased with the first cut from 30 inches to 29 inches. The tester noted: “The 300 SMK load showed a slight increase from 30″ to 29″. I’ve recorded this in other tests and it seems to be more common with a heavier load. I suspect it is primarily due to the small sample sizes being used along with the relative proximity of muzzle velocities in adjacent lengths.”

Start Velocity: 2833 FPS | End Velocity: 2492 FPS | Average Loss Per Inch: 26.2 FPS*

*Velocity rose with first cut. Velocities ranged from 2,871 FPS (29″) to 2,492 FPS (17″) for a total velocity loss of 341 FPS.

RifleShooter.com crunched the velocity numbers in some interesting ways. For example they analyzed rate of velocity loss, concluding that: “after the initial rate change, the rate of the change in velocity is fairly consistent.” (View Rate of Change Graph)

How Velocity Loss Alters Long-Range Ballistics
The testers wanted to determine how the velocity reductions “affect our ability to hit targets downrange”. So, Rifleshooter.com plotted changes in elevation and wind drift at all barrel lengths. This revealed something interesting — drift increased significantly below 26″ barrel length: “Above 26″ things look pretty good, below 22″ they change quickly.”

We highly recommend you read the whole story. Rifleshooter.com put in serious time and effort, resulting in solid, thought-provoking results. The data is presented in multiple tables and graphs, revealing inch-by-inch velocities, change “deltas”, and SDs at each length.

READ .338 LM Barrel Cut-down FULL TEST REPORT >>>

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip 3 Comments »
March 7th, 2017

Six-Five Smackdown: The .260 Remington vs. 6.5×55 Swedish

6.5x55 SE, 6.5 Swedish 6.6x55mm .260 Rem Remington Laurie Holland comparison

The .260 Remington and the 6.5×55 Swedish (aka 6,5x55mm SE) are both very popular cartridges with hunters and target shooters. The 6.5×55 has a long military heritage and a great record as a hunting round. The .260 Rem, essentially a .308 Win necked down to .264 caliber, is a more recent cartridge, but it grows in popularity every year, being one of the top cartridges for tactical/practical competitions. It offers better ballistics and less recoil than the parent .308 Win cartridge. In our Shooter’s Forum, respected UK gun writer Laurie Holland provided a good summary of the differences between the two chamberings. Laurie writes:

Remington 260 CartridgeThe 6.5×55 case has 6 or 7% more capacity than the .260s, even more in practice when both are loaded to standard COALs with heavy bullets, which sees them having to seated very deep in the .260 Rem using up quite a lot of powder capacity. So loaded up for reasonable pressures in modern actions, the 6.5×55 will give a bit more performance.

The issue for many is what action length is available or wanted, the 6.5×55 requiring a long action. So sniper rifle / tactical rifle competitors will go for the .260 Rem with the option of the many good short-bolt-throw designs around with detachable box magazines (DBMs). If a bit more performance is needed, the .260 AI (photo right) can yield another 100-150 fps velocity, depending on bullet weight.

(more…)

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March 4th, 2017

Eye Dominance — Experts Explain How Dominance Affects Vision

6.5 Creedmoor Annealing

6.5 Creedmoor AnnealingThe digital archives of Shooting Sports USA contain many interesting articles. A few seasons back, Shooting Sports USA featured a “must-read” expert Symposium on Eye Dominance, as it affects both rifle and pistol shooting. No matter whether you have normal dominance (i.e. your dominant eye is on the same side as your dominant hand), or if you have cross-dominance, you’ll benefit by reading this excellent article. The physiology and science of eye dominance is explained by Dr. Norman Wong, a noted optometrist. In addition, expert advice is provided by champion shooters such as David Tubb, Lones Wigger, Dennis DeMille, Julie Golob, Jessie Duff, and Phil Hemphill.

EDITOR: We highly recommend you read this article, particularly if you think you may be cross-dominant — meaning your dominant eye is on the opposite side as your dominant hand. For example, this Editor is right-handed, but my left eye is dominant.

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February 26th, 2017

A Few Seconds at Best — The Short Operating Life of Barrels

Stopwatch barrel life

Here’s a little known fact that may startle most readers, even experienced gunsmiths: your barrel wears out in a matter of seconds. The useful life of a typical match barrel, in terms of actual bullet-in-barrel time, is only a few seconds. How can that be, you ask? Well you need to look at the actual time that bullets spend traveling through the bore during the barrel’s useful life. (Hint: it’s not very long).

Bullet-Time-in-Barrel Calculations
If a bullet flies at 3000 fps, it will pass through a 24″ (two-foot) barrel in 1/1500th of a second. If you have a useful barrel life of 3000 rounds, that would translate to just two seconds of actual bullet-in-barrel operating time.

Ah, but it’s not that simple. Your bullet starts at zero velocity and then accelerates as it passes through the bore, so the projectile’s average velocity is not the same as the 3000 fps muzzle velocity. So how long does a centerfire bullet (with 3000 fps MV) typically stay in the bore? The answer is about .002 seconds. This number was calculated by Varmint Al, who is a really smart engineer dude who worked at the Lawrence Livermore Laboratory, a government think tank that develops neutron bombs, fusion reactors and other simple stuff.

On his Barrel Tuner page, Varmint Al figured out that the amount of time a bullet spends in a barrel during firing is under .002 seconds. Al writes: “The approximate time that it takes a 3300 fps muzzle velocity bullet to exit the barrel, assuming a constant acceleration, is 0.0011 seconds. Actual exit times would be longer since the bullet is not under constant acceleration.”

We’ll use the .002 number for our calculations here, knowing that the exact number depends on barrel length and muzzle velocity. But .002 is a good average that errs, if anything, on the side of more barrel operating life rather than less.

So, if a bullet spends .002 seconds in the barrel during each shot, and you get 3000 rounds of accurate barrel life, how much actual firing time does the barrel deliver before it loses accuracy? That’s simple math: 3000 x .002 seconds = 6 seconds.

Stopwatch barrel lifeGone in Six Seconds. Want to Cry Now?
Six seconds. That’s how long your barrel actually functions (in terms of bullet-in-barrel shot time) before it “goes south”. Yes, we know some barrels last longer than 3000 rounds. On the other hand, plenty of .243 Win and 6.5-284 barrels lose accuracy in 1500 rounds or less. If your barrel loses accuracy at the 1500-round mark, then it only worked for three seconds! Of course, if you are shooting a “long-lived” .308 Win that goes 5000 rounds before losing accuracy, then you get a whopping TEN seconds of barrel life. Anyway you look at it, a rifle barrel has very little longevity, when you consider actual firing time.

People already lament the high cost of replacing barrels. Now that you know how short-lived barrels really are, you can complain even louder. Of course our analysis does give you even more of an excuse to buy a nice new Bartlein, Krieger, Shilen etc. barrel for that fine rifle of yours.

Permalink Gunsmithing, Tech Tip 2 Comments »
February 26th, 2017

RCBS Lock-Out Die Helps Prevent Faulty Charges on Progressives

RCBS Lock-out dieIf you load pistol or rifle ammo with a progressive press, we strongly recommend you get a Lock-Out Die from RCBS. This unique reloading die will prevent your progressive press from advancing if the dispensed powder charge is more or less than about 0.3 grains too high or too low. The Lock-Out Die really works. Your Editor uses it on his RCBS 2000 progressive press. I can affirm that a Lock-Out Die has “saved my bacon” a half-dozen times over the years when there was an over-charge (which could cause a Kaboom) or a low charge (which could cause a squib load).

The Lock-Out Die works by using a central die detection rod that sets its vertical position based on the height of the powder column in the case. Through an ingenious design, if the powder column height is too low or too high, the rod locks in place as you start to pull the press handle. This halts the press before the ram can lift and the cartridge plate can advance. Unlike a beeping alarm system (which can be ignored or defeated), the Lock-Out Die physically stops the movement of the press ram and prevents a bullet being seated in the “problem” case.

RCBS Lock-out dieIt takes a bit of tweaking to get the Lock-Out Die detection rod setting just right, but once it is correctly positioned, the Lock-Out Die works smoothly in the background. The Lock-Out Die won’t interfere with the loading process unless it detects a high or low charge — and then it positively stops the progressive loading cycle.

While crafted for use in RCBS progressive presses, the RCBS Lock-Out Die can also be used on a Dillon XL Progressive (see video below) or Hornady Lock-N-Load progressive — though it does take up one station which could otherwise be used for a final crimp die (after the seating die). The RCBS 2000 has one more station than a Dillon 550/650, so it’s an ideal platform for using the Lock-Out Die.

Learn More at UltimateReloader.com
On the UltimateReloader.com website, run by our friend Gavin, you’ll find an excellent two-part series on the function and set-up of the RCBS Lock-Out Die. Part One explains how the Lock-Out Die functions, using cut-away illustrations. Part Two shows how to install and adjust the Lock-Out Die on various progressive presses. The video below shows setup of the RCBS Lock-Out Die on the Dillon XL-650 progressive press.

Images © 2011 UltimateReloader.com, used by permission.
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February 25th, 2017

Flip Your Target Colors for Better Long-Range Viewing

Negative target center reverse color image

At long range, small bullet holes are much easier to see “in the white” than in the black center of the normal High Power target. When you’re practicing at long range using a scoped rifle, one way to enhance your ability to see your bullet holes is to print a “negative” version of the regulation bullseye target so that your black center is now white.

How do you create a “negative” of a target image? Many image programs, including the FREE Irfanview software, have a “Negative” function in the pull-down menu. If you don’t see a “Negative” menu option in your program, look for a “substitute colors” option. Many printers also have a “reverse colors” function. If you can’t find a solution with your computer or printer, just take a normal bullseye target to a copy shop, and the staff can easily print you a set of targets with white centers in black fields.

Pentax PF-80 ED scopeForum member Watercam has a Pentax PF-80ED spotting scope that allows him to see 6mm bullet holes in the white at 600 yards. However, 6mm holes in the black are only visible out to 400 yards or so. Accordingly, Watercam uses a modified “reversed” black-to-white target for 600-yard practice. Watercam explains: “[Using the Pentax] With my 6mm and limited mirage I see defined, 6mm holes in the white out to 600. In the black, however, I can see bullets holes at about 400. I now use reverse-color targets for training without a pit partner at the 600-yard line.”

The Hi-Viz Solution — Day-Glo Pasters
If you’re not concerned with official scoring rings, you can use an all-white target with a bright, fluorescent target dot in the middle. A 2″- or 3″-diameter stick-on target dot is highly visible at 600 yards. Birchwood Casey Target Spots® assortment #33928-TSA offers neon orange target dots in 1″, 2″, and 3″ diameters.

Easel Pad flip chart target paper

TARGET TIP — Use Chart Paper
For practice backers for the Day-GLo pasters at long distance, use Flip Chart Paper (aka Easel Pads) marked with graph lines at 1″ intervals. Available either regular or self-stick, one sheet can hold 4-8 pasters and the white paper allows for easy spotting of the holes and quick estimation of group size. Get Flip Chart Paper at Amazon.com, Staples, or Office Depot.

Brits Use White-Field Target for F-Class
In the UK, some ranges are now using a “reverse-style” target with a mostly white area. Laurie Holland says this allows shooters to see shots much more easily. Laurie reports: “Here’s a photo of the 500/600 yard F-Class match target we use in PSSA comps at Diggle Ranges with club members Chris Hull (L) and Terry Mann (R). We now use this target form at all ranges up to 1K for F-Class, and, yes you can often see your hits at 600 yards on the target before the markers pull it. Regards from England — Laurie”.

Permalink Competition, Tech Tip 2 Comments »
February 24th, 2017

TECH TIP: How to Remove a Stuck Cartridge Case from a Die

stuck72

To err is human… Sooner or later you’ll probably get a case stuck in a die. This “fix-it” article, which originally appeared in the Western Powders Blog, explains the procedure for removing a firmly stuck cartridge case using an RCBS kit. This isn’t rocket science, but you do want to follow the directions carefully, step-by-step. Visit the Western Powders Blog for other helpful Tech Tips.

Western powders, ramshot, norma, accurate

Curing the Stuck Case Blues

decapstem72Sticking a case in the sizer die is a rite of passage for the beginning handloader. If you haven’t done it yet, that’s great, but it probably will eventually happen. When it does, fixing the problem requires a bit of ingenuity or a nice little kit like the one we got from RCBS.

The first step is to clear the de-capping pin from the flash hole. Just unscrew the de-capping assembly to move it as far as possible from the primer pocket and flash hole (photo at right). Don’t try to pull it all the way out. It won’t come. Just unscrew it and open as much space as possible inside the case.

Place the die upside down in the padded jaws of a vise and clamp it firmly into place. Using the supplied #7 bit, drill through the primer pocket. Be careful not to go too deeply inside the cartridge once the hole has opened up. It is important to be aware that the de-capping pin and expander ball are still in there and can be damaged by the bit.

Drill and Tap the Stuck Case
taping72drilling72

Once the cartridge head has been drilled, a ¼ – 20 is tap is used to cut threads into the pocket. Brass is relatively soft compared to a hardened tap, so no lube is needed for the tapping process. RCBS says that a drill can be used for this step, but it seems like a bit of overkill in a project of this nature. A wrench (photo above right) makes short work of the project.

RCBS supplies a part they call the “Stuck Case Remover Body” for the next step. If you are a do-it-yourselfer and have the bit and tap, this piece is easily replicated by a length of electrical conduit of the proper diameter and some washers. In either case, this tool provides a standoff for the screw that will do the actual pulling.

pulling72fingers72

With an Allen Wrench, Finish the Job
Run the screw through the standoff and into the tapped case head. With a wrench, tighten the screw which hopefully pulls the case free. Once the case is free, clamp the case in a vice and pull it free of the de-capping pin. There is tension here because the sizing ball is oversized to the neck dimension as part of the sizing process. It doesn’t take much force, but be aware there is still this last little hurdle to clear before you get back to loading. Don’t feel bad, everyone does this. Just use more lube next time!

wholekit72unstuck72

Article find by EdLongrange. We welcome reader submissions.
Permalink Reloading, Tech Tip 4 Comments »
February 23rd, 2017

Figuring Optimal RPM with Berger Twist-Rate Stability Calculator

Berger twist rate calculator
Erik Dahlberg illustration courtesy FireArmsID.com.

Berger twist rate calculatorBerger Twist-Rate Stability Calculator
On the updated Berger Bullets website you’ll find a handy Twist-Rate Stability Calculator that predicts your gyroscopic stability factor (SG) based on mulitiple variables: velocity, bullet length, bullet weight, barrel twist rate, ambient temperature, and altitude. This very cool tool tells you if your chosen bullet will really stabilize in your barrel.

LIVE DEMO BELOW — Just enter values in the data boxes and click “Calculate SG”.

How to Use Berger’s Twist Rate Calculator
Using the Twist Rate Calculater is simple. Just enter the bullet DIAMETER (e.g. .264), bullet WEIGHT (in grains), and bullet overall LENGTH (in inches). On its website, Berger conveniently provides this info for all its bullet types. For other brands, we suggest you weigh three examples of your chosen bullet, and also measure the length on three samples. Then use the average weight and length of the three. To calculate bullet stability, simply enter your bullet data (along with observed Muzzle Velocity, outside Temperature, and Altitude) and click “Calculate SG”. Try different twist rate numbers (and recalculate) until you get an SG value of 1.4 (or higher).

Gyroscopic Stability (SG) and Twist Rate
Berger’s Twist Rate Calculator provides a predicted stability value called “SG” (for “Gyroscopic Stability”). This indicates the Gyroscopic Stability applied to the bullet by spin. This number is derived from the basic equation: SG = (rigidity of the spinning mass)/(overturning aerodynamic torque).

(more…)

Permalink Bullets, Brass, Ammo, Tech Tip No Comments »
February 21st, 2017

Why Does Load Data Vary Between Reloading Manuals?

load manual sierra reloading hornady data

Written by Sierra Bullets Ballistic Technician Duane Siercks
One of the first things new reloaders notice is that load data varies between reloading manuals. The Sierra Bullets Technicians frequently get inquiries asking us to explain why the load data appears to be inconsistent. This article explains five key factors that can influence published load data.

Example of load data variances for two 168 grain bullets:

Sierra Reloading Manual Hornady Load Reloading

Here are five reasons why the load data varies:

The Bullet
Basically, the similarities in the .30 caliber 168 grain Match bullets (for example) end with weight and diameter. The bullets likely have dimensional differences such as bearing surface length. Bearing surface has a large effect on pressure and velocity. There are also differences in boat tail, flat base, ogive and over-all lengths, which each help determine the cartridge over-all-length (COAL). With different COAL’s, we can expect changes in pressure and velocity also. In some calibers there are differences in bullet diameter with different bullet manufacturers.

It is also worth noting that bullet manufacturers do not all use the same copper alloy for their jackets. This produces more or less friction that results in load pressures and velocities. The solid copper bullets also vary quite a bit in comparison to a lead core and copper jacketed bullet.

The Gun
Each gun is unique, even if you are using the same make, model, and caliber. Special consideration should be used to consider that not all firearm chambers are the same either, creating more variables that need consideration. There can be drastic differences in the throat length. This controls the amount of “jump” that a bullet experiences when the cartridge is fired.

The Powder
Within normal manufacturing tolerances, you can see some variation in a given powders burn rate between different lots of the same powder. So naturally when two different Manuals are produced, it would be doubtful that the same lots would be tested.

The Cartridge Cases
New cases are almost always near minimum specs in dimension. A load fired in a new case would likely have slightly more pressure that when fired in a re-sized case. This would certainly be true if we were loading into fire-formed cases that have had minimal re-sizing done. Fired cases that are full length resized most of the time be slightly larger than the new unfired cases. This gives you differences in case capacity. The same powder charge placed within a new case and a full length resized case will produce different pressure levels and probably different velocities.

Conditions
Temperature can cause pressure increases or decreases. Hot temperatures tend to cause pressures to increase, while cold temperatures will usually do the opposite. Humidity and altitude can impact pressures and velocities likewise.

Conclusion
As you can see, an amazing number of variables effect any load combination. With the differences in the manuals, you’re just seeing firsthand examples of what took place when the data was collected with that particular set of components and firearm. Think of a reloading manual as a report. In essence, a reloading manual says, “We tried this particular component combination, and these are the results we obtained.”

Remember that you may or may not reach the same maximum load safely. There is no “one load fits all bullets.” The minimum load data offers a safe place to start. The maximum load data listed should always be regarded as a safety guideline and not necessarily a goal! Your gun should shoot accurately without breaching the maximum load data. The best advice is: always start low and work your load up!

If you have questions about variances in load data or other reloading questions, please call our ballistic technicians at 1-800-223-8799 or send us an email at sierra [at] sierrabullets.com.

Sierra Bullets Blog reloading information

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 1 Comment »
February 17th, 2017

Build Your Own Target Stand with Inexpensive PVC or ABS Pipe

PVC target stand
Assembly Diagram: Here are all the components of the target frame. The overall maximum assembled dimensions are roughly 26″ wide, 41″ deep, and 66″ tall (the cardboard is 2 x 3 feet).

PVC target standOne of the easiest ways to build a portable target stand is to use PVC pipe and connectors. Utah .308 Shooter “Cheese” has created a simple yet sturdy target frame, and he’s shared his design so you can build a similar frame easily and at low cost. The components are wood furring strips, 2″-diameter PVC pipes (and connections), and a 2’x3′ sheet of cardboard. The PVC base can be glued together, or, for easier transport and storage, you can leave some or all of the connections free. “Cheese” tells us: “I didn’t glue any of it together so I could disassemble it, shove it in a bag and take it anywhere.”

“All the parts are just pushed together and not glued. That way I can break it down and carry it all in a bag. Also, if a buddy (not me!) happens to shoot the stand, I can easily replace just the damaged piece. The last 6 inches of the furring strips are wittled-down a bit so they can be pushed into the upright pipes with a little friction. The cardboard is 2 x 3 feet, and I use a staple gun to attach it to the furring strips. Then I just staple the target onto the cardboard and go at it.

Of course you can modify the dimensions as desired. I chose the black ABS pipe over white PVC simply for cost — black ABS is a little cheaper. You can also glue some or all of the parts together, it’ll just be larger for transporting. In windy conditions, the thing likes to come apart. Duct tape might work well.

For weight, I thought about filling the two end pipes with sand and gluing test caps on each of their ends. The test caps still allow the pipes to slip into the elbows.”

Add Anchors or Internal Weight for Stability
On a very windy day, a PVC stand can shake or even topple over. There are a couple solutions to this. Some people fill the PVC pipe sections with sand to add weight, or you can put short sections of Re-BAR inside the long legs. One GlockTalk forum member noted: “I built [a frame] almost identical to this. I also take four pieces of wire coathanger bent into an inverted “U” shape to anchor the frame to the ground. It is so light that wind will knock the stand over [without anchors].”

You can find photos of a similar home-made PVC target stand (with a slightly different rear section) on the Box of Truth website. This also employs a PVC tubing base with wood uprights. We’ve also seen all-PVC target stands, but we’ve found that it is easier to attach the cardboard to wood strips than to PVC pipe. Also, if the upper section is wood, you can fit different height targets, while using the same base.

Permalink Tactical, Tech Tip 1 Comment »
February 9th, 2017

Ballistics Brain Power — Take Our Ballistics Quiz

Ballistics Quiz Bryan Litz Applied Ballistics

At the Berger SW Nationals this week in Phoenix, the nation’s top long-range shooters will try to put all their shots in the 10-Ring at 800, 900, and 1000 yards. A good foundation in ballistics is vital if you want to succeed in the long-range game.

How much do you know about BCs, Bullet Shapes, Trajectories, Wind Drift, and other things in the realm of External Ballistics? You can test your knowledge of basic Ballistics principles with this interactive quiz. The questions and answers were provided by Ballistics Guru Bryan Litz of Applied Ballistics LLC. Bryan is the author of Applied Ballistics for Long-Range Shooting and other popular resources in print, DVD, and eBook format. Have fun with our Quiz.

The Quiz contains ten (10) questions. When you complete all ten questions, you can see your results, along with the correct answers.

Permalink Bullets, Brass, Ammo, Tech Tip 2 Comments »
February 4th, 2017

How to Fire-Form Brass without Bullets

Fire-Form Brass Cream of Wheat Dasher BRDX

Many of our Forum members shoot an “improved” 6mmBR cartridge. This might be a 30°-shoulder 6mm BRX, or a 40°-shoulder 6mm Dasher, or the 6mm BRDX, which is very similar to the Dasher, but with a slightly longer neck. This Editor shoots a 6mm BRDX and has found it very accurate, and maybe a bit easier to fire-form than a standard Dasher. Speaking of fire-forming, in our Shooters’ Forum, we often see questions about fire-forming BRX/Dasher brass. For those who need a large number of BRX or Dasher cases, one option to consider is using pistol powder in a dedicated fire-forming barrel. Here’s an explanation of how this process can work.

Forum member Skeeter has a 6mm Dasher falling block varmint rifle. The Dasher case is based on the 6mmBR Norma cartridge with the shoulder blown forward about 0.100″ and out to 40°. This gives the Dasher roughly 3.5 grains added capacity compared to the standard 6BR.

A few seasons back, Skeeter needed to form 300 cases for varmint holiday. Skeeter decided to fire-form his brass without bullets. This method avoids barrel wear and saves on components. There are various ways to do this, but Skeeter chose a method using pistol/shotgun powder, some tissue to hold the powder in place, Cream of Wheat filled to within an 1/8″ of top of the neck, and a “plug” of tissue paper to hold it all in place. Shown below are cases filled with a pistol/shotgun powder charge topped with Cream of Wheat and then a tissue paper plug.

To ensure the case headspaced firmly in his Dasher chamber, Skeeter created a “false shoulder” where the new neck-shoulder junction would be after fire-forming. After chamfering his case mouths, Skeeter necked up all his cases with a 0.257″ mandrel (one caliber oversized). Then he used a bushing neck-sizing die to bring the top half of the neck back down to 0.267″ to fit his 0.269″ chamber. The photo below shows how the false shoulder is created.

After creating the false shoulder, Skeeter chambered the cases in his rifle to ensure he could close the bolt and that he had a good “crush fit” on the false shoulder, ensuring proper headspace. All went well.

The next step was determining the optimal load of pistol powder. Among a variety of powders available, Skeeter chose Hodgdon Titewad as it is relatively inexpensive and burns clean. The goal was to find just the right amount of Titewad that would blow the shoulder forward sufficiently. Skeeter wanted to minimize the amount of powder used and work at a pressure that was safe for his falling block action.

Working incrementally, Skeeter started at 5.0 grains of Titewad, working up in 0.5 grain increments. As you can see, the 5.0 grain charge blew the shoulder forward, but left it a hemispherical shape. At about 7.0 grains of Titewad, the edge of the shoulder and case body was shaping up. Skeeter decided that 8.5 grains of Titewad was the “sweet spot”. He tried higher charges, but the shoulder didn’t really form up any better. It will take another firing or two, with a normal match load of rifle powder and a bullet seated, to really sharpen up the shoulders. Be sure to click on the “View Larger Image” link to get a good view of the cases.


The process proved to be a success. Skeeter now has hundreds of fire-formed Dasher cases and he hasn’t had to put one bullet through his nice, new match-grade barrel. The “bulletless” Cream of Wheat method allowed him to fire-form in a tight-necked barrel without neck-turning the brass first. The only step now remaining is to turn the newly Dasher-length necks down about .0025″ to fit his 0.269″ chamber. (To have no-turn necks he would need an 0.271″ or 0.272″ chamber).

Skeeter didn’t lose a single case: “As for the fire-forming loads, I had zero split cases and no signs of pressure in 325 cases fire-formed. Nor did I have any misfires or any that disbursed COW into the action of the firearm. So the COW method really worked out great for me and saved me a lot of money in powder and bullets.”

Skeeter did have a fire-forming barrel, but it was reamed with a .269 chamber like his 10-twist Krieger “good” barrel. If he fire-formed with bullets, he would have to turn all 300 necks to .267″ BEFORE fire-forming so that loaded rounds would fit in the chamber. Judging just how far to turn is problematic. There’s no need to turn the lower part of the neck that will eventually become shoulder–but how far down the neck to turn is the issue. By fire-forming without bullets now he only has to turn about half the original neck length, and he knows exactly how far to go.

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 4 Comments »