May 29th, 2016

Barrel Length and Velocity in a .223 Rem — Barrel Cut-Down Test

.223 Rem Cut-Down Test barrel UMC m855

We often receive questions from varmint hunters and AR shooters regarding barrel length. They want to know how much velocity they will loose if they run a shorter barrel in their .223-Rem rifle. Our friends at Rifleshooter.com did a test that provides some surprising answers to that question.

With barrels, one always wonders “Can a little more length provide a meaningful velocity gain?” To help answer that question, Rifleshooter.com performed an interesting test, cutting the barrel of a .223 Rem rifle from 26″ all the way down to 16.5″. The cuts were made in one-inch intervals with a rotary saw. At each cut length, velocity was measured with a Magnetospeed chronograph. To make the test even more interesting, four different types of .223 Rem/5.56 ammo were chron’d at each barrel length.

READ RifleShooter.com 5.56/.223 Barrel Cut-Down Test Article.

Test Barrel Lost 25.34 FPS Per Inch (.223 Rem Chambering)
How much velocity do you think was lost, on average, for each 1″ reduction in barrel length? The answer may surprise you. The average speed loss of the four types of .223/5.56 ammo, with a 9.5″ shortening of barrel length, was 240.75 fps total (from start to finish). That works out to an average loss of 25.34 fps per inch. (See inch-by-inch data HERE.)

5.56/.223 Barrel Cut-Down Speed Test 26″ to 16.5″ Start FPS at 26″ End FPS at 16.5″ Total Loss Average Loss Per Inch
UMC .223 55gr 3182* 2968 214 22.5 FPS
Federal M193 55gr 3431 3187 244 25.7 FPS
Win m855 62gr 3280 2992 288 30.3 FPS
Blk Hills .223 68gr 2849 2632 217 22.8 FPS

*There may have been an error. The 25″ velocity was higher at 3221 fps.

Rifleshooter.com observed: “Cutting the barrel from 26″ to 16.5″ resulted in a velocity reduction of 214 ft/sec with the UMC 223 55-grain cartridge, 244 ft/sec with the Federal M-193 cartridge, 288 ft/sec with the Winchester M855 cartridge and 217 ft/sec with the Back Hills 223 68-grain match cartridge.”

How the Test Was Done
The testers described their procedure as follows: “Ballistic data was gathered using a Magnetospeed barrel-mounted ballistic chronograph. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. Average velocity and standard deviation were logged for each round. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. The barrel was cut off using a cold saw. The test protocol was repeated for the next length. Temperature was 45.7° F.”

CLICK HERE to Read the Rifleshooter.com Test. This includes detailed charts with inch-by-inch velocity numbers.

Much Different Results with 6mmBR and a Longer Barrel
The results from Rifleshooter.com’s .223/5.56 test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. When we cut our 6mmBR barrel down from 33″ to 28″ we only lost about 8 FPS per inch. Obviously this is a different cartridge type, but also our 6mmBR barrel end length was longer than Rifleshooter.com’s .223 Rem start length. Velocity loss may be more extreme with shorter barrel lengths.

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May 23rd, 2016

How To Pull Bullets Using Press-Mounted Collet Tools

Collet Bullet Puller Hornady RCBS Press Mount Reloading

Do you have some ammo that got loaded incorrectly, perhaps with the wrong powder? Then you’ll want to disassemble the ammo for safety’s sake. You can use an impact puller to do this task, but if you have more than a dozen rounds or so, you may prefer to use a collet-style bullet puller. These work very quickly and positively, making quick work of big jobs. The efficiency of the collet-style puller is worth the investment if you frequently disassemble ammo. These devices retail for under $25.00 (collets sold separately). Normally, you’ll need a specific collet for each bullet diameter. But collets are not that costly, so this isn’t a big deal, particularly if you only load a few calibers, such as .223, 6mm, and .308.

Hornady and RCBS use different mechanisms to tighten the collet around the bullet. On Hornady’s Cam-Lock Bullet Puller, a lever-arm on the top of the bullet puller serves to tighten the collet around the bullet. Simply rotate the lever from the vertical to the horizontal position to grab the bullet. Lower the ram to remove the case. The bullet will drop out when you return the lever arm to the vertical position. This is demonstrated in the video below:

Hornady Cam-Lock Bullet Puller Demonstrated

Collet bullet-pullers resemble a loading die with a lever or handle on the top. They screw into a standard reloading press. Hornady and RCBS both make collet-style bullet pullers. They use the same basic principle — the device tightens a collet around the bullet, and then the bullet is separated from the case by lowering the press ram. NOTE: Collet pullers may leave small marks on your bullets, unlike impact (kinetic) pullers.*

(more…)

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May 22nd, 2016

Harris Bipod Adapter for Flat-Bottomed Stocks

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 $21.26 (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:

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

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

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May 11th, 2016

Bullet Seating Advice — How to Avoid Ring Marks on Your Bullets

Seating Stem Reloading Tip Sierra Bullet .223 Remington compressed loads

Here’s a helpful hint for hand-loaders from Sierra Bullets. While this article focuses on Sierra’s new Tipped Match-King bullets, the recommended solutions apply to other bullet types as well. The article explains how sharp edges on a seating stem can cause a ring to be pressed into the bullet jacket — especially with compressed loads that resist downward bullet movement. Here Sierra technician Rich Machholz diagnoses the problem and provides a solution.

Solutions for Ring Marks Caused by Seating Stems

by Sierra Bullets Ballistic Technician Rich Machholz
Now that the new Tipped MatchKing® (TMK) bullets are being shipped and shooters are putting them to use I have received several calls regarding marking on the bullet ogive from the seating stem.

The cause can be traced to one of several things.

In the .223 and especially with the long, 77 grain TMK seated at 2.250” or even 2.260” most loads of Varget® and Reloder® 15 are compressed loads, sometimes heavily compressed. This puts a great deal of pressure on the bullet through the seating stem. The result of all this pressure is a mark of varying depth and appearance on the ogive of the bullet. [Editor: We have seen this issue with a variety of other bullet types/shapes as well, including non-tipped VLDs. The solution is profiling the internal cone of the seating stem to match your bullet shape.]

Some older seating stems might even bear against the tip of the bullet which can make a slight bulge in the jacket just below the junction of the resin tip and the copper jacket in a compressed load. If this is the case there is not a ready fix other than calling the die manufacturer and requesting a new deeper seating stem.

Polish Your Seating Stem to Remove Sharp Internal Edges
If the seating stem is of proper depth the culprit most generally is a thin sharp edge on the inside taper of the seating stem. This is an easy fix that can be accomplished by chucking a spare 77 grain bullet in your drill, coating it with valve grinding compound or even rubbing compound or in a pinch even tooth paste.* Remove the seating stem assembly from the seating die. Turn the drill on and put the seating stem recess over the spinning bullet with the polishing compound to break or smooth the sharp edge that is making the offending mark. This might take more than one application to get the proper polish depending upon what you use, but the more you polish the better the blend of angles which will [ensure the stem matches the bullet contours, not leaving a sharp ring].

Seating Stem Reloading Tip Sierra Bullet .223 Remington compressed loads

If the above is a little more than you care to tackle you might try very fine emery cloth twisted to a point that can be inserted into the mouth to the seating stem and rotated to polish the inside to eliminate any sharp edges that might be present.

Load Advice for 77gr TMKs in the .223 Rem
And last but certainly not least. Actually, even though we don’t say you need additional data for the TMKs, remember you are dealing with heavily-compressed loads in some cases because of the additional bullet length. Due to the additional length of these new bullets and in the interest of gaining some room in the case you might consider trying a slightly faster extruded powder like BenchMark or the 4895s or an even more dense powder like the spherical H335®, CFE223 or TAC. The extra room will allow for trouble free bullet seating also.

Good luck and remember we are no further away than your telephone: 1-800-223-8799.

Sierra Bullets Match-King Reloading Bullet Seating

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May 7th, 2016

A Look Inside Sierra’s 300m Underground Test Tunnel

Sierra Bullets Test Tunnel Barrels

Ever wonder how (and where) Sierra tests its bullets? The answer is underground, in a 300-meter test tunnel located under Sierra’s factory in Sedalia, Missouri. The photo above shows the construction of the tunnel back in May, 1990. Like most bullet manufacturers, Sierra does live-fire bullet testing to ensure that Sierra projectiles perform as promised, with repeatable accuracy. Sierra’s 300-meter test range is the longest, privately-owned underground bullet test facility in the world. Sierra offers free tours of the test tunnel as part of Sierra’s Factory Tour Program.

Sierra Bullets indoors testing barrels

Sierra Bullets tests every new bullet design and each lot of bullets. Sierra tells us: “When [we] change to a new bullet they are continually shooting them until they get the bullet properly set up and running and the range releases them to run (meaning the bullets shoot to spec). [Testers] are required to shoot at any lot change and periodically throughout the lot … even if it is just a press operator change. Lot sizes can vary from 5,000 to over 100,000 thousand. If anything changes — it is a new lot. When a new operator comes on — it is a new lot.”

Bevy of Barreled Actions for Bullet Testing
Sierra Bullets uses dozens of barreled actions for testing bullets. These barreled actions are clamped in stout, return-to-battery test fixtures. These heavy test fixtures provide near-perfect repeatability (with no human-induced holding or aiming errors). Each barrel has its own logbook to track the barrel’s usage. Interestingly, Sierra does not have a specific round count for barrel life. When a barrel starts “opening up”, i.e. showing a decline in accuracy, then the barrel is replaced, whether it has 800 rounds through it or 5,000.

Sierra Bullets indoors testing barrels
Click Photo to Zoom

Sierra Bullets 10-Shot Groups at 200 yards
What kind of 200-yard accuracy can you get in an enclosed, underground test range? Would you believe 0.162 MOA at 200 yards with a .338? Check out these 10-shot test groups shot at the Sierra Test Range at 200 yards. Note that the numbers listed on each sample are actual measurements in inches. To convert to MOA, cut those numbers in half (to be more precise, divide by 2.094, which is 1 MOA at 200 yards). For example, the 0.340″ middle group works out to 0.162 MOA at 200 yards.

Sierra Bullets indoors testing barrels

Permalink Bullets, Brass, Ammo, Tech Tip 11 Comments »
May 7th, 2016

Practical D.O.P.E. Video Offers Tips on Ballistics Data

In this NSSF Video, Ryan Cleckner, a former Sniper Instructor for the 1st Ranger Battalion, explains how to gather and organize D.O.P.E. (Data On Previous Engagements) and how to organize this information to make it readily available in the field. As the term is used by Cleckner, D.O.P.E. includes observed bullet drop information at various distances, as well as the effects of wind, temperature changes, humidity and other environmental variables.

If you know your muzzle velocity, and bullet BC, a modern Ballistics App should be able to calculate bullet drop with great precision at distances from 100-1000 yards — often within a couple 1/4-MOA clicks. However, because a bullet’s BC is actually dynamic (changing with speed), and because ballistics solvers can’t perfectly account for all variables, it’s useful to collect actual, verified bullet drop data.

It’s smart to start with ballistics data from a solver app, but, as Cleckner explains: “Odds are, you’re going to have to fine-tune that data to your gun and your system. Every scope and every rifle and every bullet [type] act differently. Your scope may not track the same from rifle to rifle, so it’s important you get the data that’s unique to you.” Cleckner also explains that the ballistic data supplied with some factory ammo may only give you a crude approximation of how that ammo will actually shoot through your gun.

drop chart scope coverKeeping Your Drop Data with the Rifle
Cleckner also offers some good advice on how to record D.O.P.E. on simple index cards, and how to keep your ballistics data with your rifle. This can be done with a laminated drop chart or data transferred to a scope cover (photo right). CLICK HERE, to learn more about creating handy field data cards.

At the 4:15 mark on the video, Cleckner shows a calibrated tape he has fitted around the turret of his riflescope. The tape shows distance numbers (e.g. “4” for 400 yards, “5” for 500 yards etc.) that correspond with the number of clicks (rotation) required to be zeroed at that particular distance. With that system, you simply “dial your distance” and your point of impact should equal your point of aim. It takes some skill (and the right software) to create these tapes, but the concept is great.

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May 5th, 2016

Check Your Crown’s Condition with a Q-Tip

The last half-inch or so of your barrel is absolutely critical. Any damage (or abnormal wear) near the crown will cause a significant drop-off in accuracy. Here are ways you can check the end of your barrel, using a common Q-Tip.

Use Q-Tip for Barrel Inspection
To find out if you have a burr or damage to your crown, you can use an ordinary Q-tip cotton swab. Check the edges of the crown by pulling the Q-tip gently out past the edge of the crown. If you have a burr, it will “grab” the cotton and leave strands behind.

Larry Willis has another way to use a Q-Tip: “Here’s a neat trick that will surprise you with how well it works.” Just insert a Q-Tip into your barrel (like the picture below), and it will reflect enough light so that you can get a real good look at the last half inch of rifling and the crown of your barrel. In most cases you’ll find that this works much better than a flashlight. Larry tells us: “I’ve used this method about a jillion times. Q-Tips are handy to keep in your cleaning supplies anyway. This is a good way to judge approximately how well you are cleaning your barrel when you’re at the range. It’s also the best way to examine your barrel when you’re in the field.”

Larry Willis is the inventor of Innovative Technologies’ Belted Magnum Collet Resizing Die. Larry explains how this die works, and offers other reloading tips on LarryWillis.com.

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May 4th, 2016

Get Smart: Read Top TECH Articles on AccurateShooter.com

AccurateShooter.com technical articles Case Prep Stock Bedding Savage Tuning Painting

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 100 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.

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.

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.

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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May 2nd, 2016

Pistol Powder in a Rifle Cartridge — The Handloader’s Nightmare

This is a grim tale. A man almost lost the use of his right hand, and did suffer terrible injuries to his fingers. All because he picked the wrong bottle of powder off the shelf.

Varget Kaboom TiteGroup Hand injury reloading fingers accident

Similar Labels, Disasterous Consequences
The shooter, Denny K., was assembling some rounds for his brand new 7mm-08 Savage hunting rifle. He thought he was loading with Hodgdon Varget. Instead he had filled his powder measure with Hodgdon TiteGroup, a fast-burning pistol powder. The labels are similar, so the mistake is understandable. But the results were devastating. Here’s what 41 grains of TiteGroup can do in a 7mm-08:

Varget Kaboom TiteGroup Hand injury reloading fingers accident

Posting on the Firing Line, in a thread entitled “Lucky to Be Alive”, Denny writes:

“This is the hardest post to post. I know if I had read it a week ago my comment would have been: ‘You have no business reloading’. I had everything perfect, except pouring the wrong powder in the powder measure. I type this slowly with my left hand, embarrassed but … possibly saving someone else a tragedy or, like me, a long drive to the Emergency Room and surgery to save my finger.”

CLICK HERE for bigger, more graphic photo of injury.
Varget Kaboom TiteGroup Hand injury reloading fingers accident

The Still-Sealed Bottle of Varget
Denny did not initially comprehend exactly why the kaboom happened. He thought maybe his new Savage rifle was at fault. Then, on his return home, he discovered something…

Denny wrote: “The seven-hour period it took to go to ER, transport to Trauma Center and surgery made me think it was a Savage rifle issue. Brand new rifle, new brass, triple-checked loading data. The next day I was humbled when I realized the Varget powder was still sealed.

I knew what powder to use. I thought [Varget] was what I used. Not until the following day did I realize the Varget was still sealed.”

At that point, Denny realized what caused the accident — “operator error”. He knew he had to warn others about using the wrong powder: “I knew I needed to share my mistake, even though it is embarrassing, just to remind people. I’ve been reloading for 30 years…”

Editor’s Comment: Denny was not a novice reloader. His experience demonstrates that this kind of mistake can be made by any hand-loader, even one with decades of experience. Be safe guys, take your time when you load your ammo. Remove powders from measures after your loading sessions (pistol powders can look very similar to rifle powders). And by all means CHECK the LABEL on the jug. As the TiteGroup label says: “A little goes a long way.”

It’s not a bad idea to separate your pistol powders from your rifle powders, or perhaps even load for pistol in a separate part of your workshop.

Permalink Reloading, Tech Tip 11 Comments »
April 29th, 2016

Sinclair Int’l Offers 8-Part Series of Reloading Videos

Sinclair International has created a series of instructional videos illustrating the basics of metallic cartridge reloading. The 8-part series starts with reloading basics and provides step-by-step, how-to instructions that will help new reloaders get started. Detailed, animated illustrations show you what happens inside the chamber when shooting, and inside the dies during each step of reloading. The videos can be viewed on Sinclair Int’l’s YouTube page. Shown below is the first video in the series:

Each of the eight videos is hosted by Sinclair Int’l President Bill Gravatt. Bill doesn’t just show you “how”, he tells you “why”. The how-to segments cover case inspection, proper die set up, case sizing, primer installation, powder measuring, bullet seating, crimping, and even goes into the record keeping needed for the handloader. “We wanted to give shooters who haven’t reloaded a look at all the advantages of creating your own ammo and how easy it is to get started,” said Gravatt, “without telling them they had to have any certain brand or type of equipment to do the job.” The eight videos are:

Part 1 — Intro to Video Series
Part 2 — Intro to Reloading Safety
Part 3 — Metallic Cartridge Components
Part 4 — The Firing Sequence
Part 5 — Tools for Reloading
Part 6 — Loading Bottle-Neck Cartridges
Part 7 — Loading Straight Wall Cartridges
Part 8 — Reloading Series Conclusion

Reloading Tools
Shown below is Part 5 of the video series, covering the tools used for precision reloading.

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April 28th, 2016

How Do Bullets Fly — Mysteries Revealed by German Ballistician

Bullet External Ballistics
“The overturning moment MW tends to rotate the bullet about an axis, which goes through the CG (center of gravity) and which is perpendicular to the plane of drag….

Ruprecht Nennstiel, a forensic ballistics expert from Wiesbaden, Germany, has authored a great resource about bullet behavior in flight. Nennstiel’s comprehensive article, How Do Bullets Fly, explains all the forces which affect bullet flight including gravity, wind, gyroscopic effects, aerodynamic drag, and lift. Nennstiel even explains the rather arcane Magnus Force and Coriolis Effect which come into play at long ranges. Nennstiel’s remarkable resource contains many useful illustrations plus new experimental observations of bullets fired from small arms, both at short and at long ranges.

Shadowgraph of .308 Winchester Bullet

Bullet External Ballistics

A convenient index is provided so you can study each particular force in sequence. Writing with clear, precise prose, Nennstiel explains each key factor that affects external ballistics. For starters, we all know that bullets spin when launched from a rifled barrel. But Nennstiel explains in greater detail how this spinning creates gyroscopic stability:

“The overturning moment MW tends to rotate the bullet about an axis, which goes through the CG (center of gravity) and which is perpendicular to the plane of drag, the plane, formed by the velocity vector ‘v’ and the longitudinal axis of the bullet. In the absence of spin, the yaw angle ‘δ’ would grow and the bullet would tumble.

If the bullet has sufficient spin, saying if it rotates fast enough about its axis of form, the gyroscopic effect takes place: the bullet’s longitudinal axis moves into the direction of the overturning moment, perpendicular to the plane of drag. This axis shift however alters the plane of drag, which then rotates about the velocity vector. This movement is called precession or slow mode oscillation.”

Raise Your Ballistic IQ
Though comprehensible to the average reader with some grounding in basic physics, Nennstiel’s work is really the equivalent of a Ph.D thesis in external ballistics. You could easily spend hours reading (and re-reading) all the primary material as well as the detailed FAQ section. But we think it’s worth plowing into How Do Bullets Fly from start to finish. We suggest you bookmark the page for future reference. You can also download the complete article for future reference and offline reading.

CLICK HERE to download “How Do Bullets Fly” complete text. (1.2 MB .zip file)

Photo and diagram © 2005-2009 Ruprecht Nennstiel, All Rights Reserved.

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April 27th, 2016

Press-Mounted Bullet Pullers — How to Use Them

Collet Bullet Puller Hornady RCBS Press Mount Reloading

In our Shooters’ Forum, a member recently noted that he needed to pull down (disassemble) some ammunition that was loaded incorrectly by one of his shooting buddies. You can use an impact puller to do this task, but if you have more than a dozen rounds or so, you may prefer to use a collet-style bullet puller. These work very quickly and positively, making quick work of big jobs. The efficiency of the collet-style puller is worth the investment if you frequently disassemble ammo. These devices retail for under $25.00 (collets sold separately). Normally, you’ll need a specific collet for each bullet diameter. But collets are not that costly, so this isn’t a big deal, particularly if you only load a few calibers, such as .223, 6mm, and .308.

Hornady and RCBS use different mechanisms to tighten the collet around the bullet. On Hornady’s Cam-Lock Bullet Puller, a lever-arm on the top of the bullet puller serves to tighten the collet around the bullet. Simply rotate the lever from the vertical to the horizontal position to grab the bullet. Lower the ram to remove the case. The bullet will drop out when you return the lever arm to the vertical position. This is demonstrated in the video below:

Hornady Cam-Lock Bullet Puller Demonstrated

Collet bullet-pullers resemble a loading die with a lever or handle on the top. They screw into a standard reloading press. Hornady and RCBS both make collet-style bullet pullers. They use the same basic principle — the device tightens a collet around the bullet, and then the bullet is separated from the case by lowering the press ram. NOTE: Collet pullers may leave small marks on your bullets, unlike impact (kinetic) pullers.*

Hornady collet bullet pullerLike the Hornady tool, the RCBS Bullet Puller employs a collet to grab the bullet. However, the RCBS tool tightens the collet in a different way. The head of the RCBS tool is threaded internally. By rotating the lever arm clockwise in a horizontal circle you squeeze the collet around the bullet. To remove the bullet, after lowering the press ram, simply spin the lever arm back in the opposite direction. The use of the RCBS tool is demonstrated in this video:

RCBS Collet Bullet Puller Demonstrated:

WARNING: When removing bullets from loaded cartridges, always make sure there are no obsructions or debris in your shell-holder or under the loaded round. NEVER engage a primer seating accessory on your press when working with loaded rounds. You can cause a round to discharge by contacting the primer! Also, we recommend you keep your head and torso away from the bullet puller tool at all times.

*By contrast, impact pullers rarely mark bullets, particularly if you put a little bit of foam or paper wadding in the closed end of your impact puller. When dismantling loaded rounds, powder kernels can get trapped in the wadding, so you should remove and replace the wadding before changing to cartridges loaded with a different powder type (assuming you intend to save the powder).

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April 26th, 2016

How NOT to Ventilate Your Chronograph — Set-Up Tips

chronograph placement, shooting chrony, chrono, advisory, tech tip

There is nothing more frustrating (or embarassing) than sending a live round into your expensive new chronograph. As the photo below demonstrates, with most types of chronographs (other than the barrel-hung Magnetospeed), you can fatally injure your expensive chrono if it is not positioned precisely.

When setting up a chrono, we always unload the rifle, remove the bolt and bore-sight to ensure that the path of the bullet is not too low. When bore-sighting visually, set up the rifle securely on the sandbags and look through the bore, breech to muzzle, lining up the barrel with your aim point on the target. Then (during an appropriate cease-fire), walk behind the chronograph. Looking straight back through the “V” formed by the sky-screens, you should be able to see light at the end of the barrel if the gun is positioned correctly. You can also use an in-chamber, laser bore-sighter to confirm the visual boresighting (see photo).

Laser boresighter chronograph

Adjust the height, angle and horizontal position of the chronograph so the bullet will pass through the middle of the “V” below the plastic diffusers, no less than 5″ above the light sensors. We put tape on the front sky-screen supports to make it easier to determine the right height over the light sensors.

Use a Test Backer to Confirm Your Bullet Trajectory
You can put tape on the support rods about 6″ up from the unit. This helps you judge the correct vertical height when setting up your rifle on the bags. Another trick is to hang a sheet of paper from the rear skyscreen and then use a laser boresighter to shine a dot on the paper (with the gun planted steady front and rear). This should give you a good idea (within an inch or so) of the bullet’s actual flight path through the “V” over the light sensors. Of course, when using a laser, never look directly at the laser! Instead shine the laser away from you and see where it appears on the paper.

chronograph set-up

Alignment of Chronograph Housing
Make sure the chrono housing is parallel to the path of the bullet. Don’t worry if the unit is not parallel to the ground surface. What you want is the bullet to pass over both front and rear sensors at the same height. Don’t try to set the chrono height in reference to the lens of your scope–as it sits 1″ to 2″ above your bore axis. To avoid muzzle blast interference, set your chronograph at least 10 feet from the end of the muzzle (or the distance recommended by the manufacturer).

chronograph laser sky screens

Rifles with Elevated Iron Sights
All too often rookie AR15 shooters forget that AR sights are positioned roughly 2.4″ above the bore axis (at the top of the front sight blade). If you set your bullet pass-through point using your AR’s front sight, the bullet will actually be traveling 2.4″ lower as it goes through the chrono. That’s why we recommend bore-sighting and setting the bullet travel point about 5-8″ above the base of the sky-screen support shafts. (Or the vertical distance the chronograph maker otherwise recommends). NOTE: You can make the same mistake on a scoped rifle if the scope is set on very tall rings, so the center of the cross-hairs is much higher than the bore axis line.

Laser boresighter chronograph

TARGET AIM POINT: When doing chrono work, we suggest you shoot at a single aiming point no more than 2″ in diameter (on your target paper). Use that aiming point when aligning your chrono with your rifle’s bore. If you use a 2″ bright orange dot, you should be able to see that through the bore at 100 yards. Using a single 2″ target reduces the chance of a screen hit as you shift points of aim. If you shoot at multiple target dots, place them in a vertical line, and bore sight on the lowest dot. Always set your chron height to set safe clearance for the LOWEST target dot, and then work upwards only.

Other Chronograph Tips from Forum Members:

When using a chronograph, I put a strip of masking tape across the far end of the skyscreens about two-thirds of the way up. This gives me a good aiming or bore-sighting reference that’s well away from the pricey bits. I learned that one the hard way. — German Salazar

A very easy and simple tool to help you set up the chronograph is a simple piece of string! Set your gun (unloaded of course) on the rest and sight your target. Tie one end of the string to the rear scope ring or mount, then pull the string along the barrel to simulate the bullet path. With the string showing the bullet’s path, you can then easily set the chronograph’s placement left/right, and up/down. This will also let you set the chrono’s tilt angle and orientation so the sensors are correctly aligned with the bullet path. — Wayne Shaw

If shooting over a chrono from the prone position off a bipod or similar, beware of the muzzle sinking as recoil causes the front of the rifle to drop. I “killed” my first chronograph shooting off a gravel covered firing point where I’d not given enough clearance to start with and an inch or two drop in the muzzle caused a bullet to clip the housing. — Laurie Holland

Permalink Bullets, Brass, Ammo, Tech Tip 2 Comments »
April 25th, 2016

Field Target Tip: How to Range Targets Using the Scope

Target Ranging, Range, Scope, Optic field target UK

This article appears courtesy Target Shooter magazine from the UK.

Field Target (FT) and Hunter Field Target (HFT) airgun disciplines are popular outdoor shooting sports that simulate the challenges of hunting small game. One of the unique aspects of FT competition is target range-finding using parallax and optical focus. (HFT is limited to lower power scopes, so this type of range-fiding is not used in HFT.) Range-finding is very important because the pellets shot by FT airguns drop rapidly once they leave the muzzle (pellets can drop roughly 5″ at 50 yards). If you don’t have your scope set to the correct distance, you’ll probably miss the target high or low.

FT competitors employ high-magnification (35-55X) scopes to sight targets placed from 10 to 55 yards (7.3 to 50m in the UK). Because these scopes have very short depth-of-field at high-magnification, the target will be out of focus unless you have the scope focus/parallax control set very precisely. But competitors can use this to their advantage — once the target is precisely focused, you have effectively established its distance from the shooter. FT scopes often have large-diameter wheels on the side parallax control so the focus can be set very precisely. You can then read marks placed on the scope to adjust the amount of elevation need to put the pellet on target.

To simplify the adjustment of elevation on FT rifles, competitors will place tapes on the windage knobs with marks that correspond to distances in 3-5 yard (or smaller) increments. These marks allow you to quickly spin your elevation to the setting matching the target range established with your focus/parallax control.

Field Target Accessories
There are a variety of specialized products for FT competitors that help you set up your scope for precise ranging. First, Compufoil offers a computer program, ScopeKnob, that lets you easily create accurate elevation knob tapes for your scope. ScopeKnob even comes with a built-in Ballistics Module that will calculate the pellet trajectory for you and plot range settings for your tape. Chairgun.com also offers ChairGunPRO, specialized airgun ballistics software that lets you simultaneously compare four different pellets, or different scope heights.

Field Target Scope knobIn the past, the A-Team offered replacement elevation knobs optimized for use with yardage marking tapes. These were offered in two versions, one which replaced the existing turret altogether and a second which clamped OVER the factory turret. Shown at right is the larger-diameter version in place over the factory turret. Unfortunately we don’t know a current source for this product, but this may help you crate something similar on your own.

Last but not least, Pyramid Air offers large-diameter parallax control wheels. According to Pyramid: “The enlarged sidewheel is the most popular FT scope accessory of all. It lets you put white artist’s tape around the rim to mark the actual distances at which the scope focuses”. A 6″ sidewheel provides over 18″ of space on which to inscribe yardage, and that means you can have a meaningful separation between 18 yards and 20 — where there is a huge parallax and trajectory difference. Though the ranges are already engraved on the rim of the wheel, field target competitors will measure them again on an actual range and write the markings on a strip of white artist’s tape.

Tips on Field Target Scope Set-Up
The creator’s of the A-Team knobs suggest taking your time when setting up a scope for Field Target competition: “We normally take from three to four hours preparing a scope to be mounted on a gun. We mark the scope in 1-yard increments from 9 to 40 yards, then to 55 yards by 3 or 5-yard increments depending on the scope being calibrated.”

Permalink Competition, Optics, Tech Tip No Comments »
April 23rd, 2016

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 3 Comments »
April 22nd, 2016

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…)

Permalink - Articles, Reloading, Tech Tip 4 Comments »
April 21st, 2016

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 »
April 14th, 2016

Weaver vs. Picatinny Scope Rails

Picatinny Rail specifications 1913 Mil-std

Readers often ask “What’s the difference between a Weaver scope rail and a Picatinny Rail?” The answer is not as simple as it seems. The dimensions of a Picatinny Rail should be consistent (from one rail-maker to another), since there IS a government spec. Conversely, there is some variance in “Weaver-style” rails. The width of the groove is the most important difference between Picatinny Rails and weaver rails. “Mil-spec” Picatinny rails will have a grove width of 0.206″ while Weaver rails typically have a narrower, 0.180″ groove width.

Brownell’s has a helpful GunTech™ Article that discusses the Picatinny Rail vs. Weaver Rail. That article explains:

“What are the differences between the ‘Picatinny’ and the ‘Weaver’ systems? The profile of the two systems is virtually identical. Depending on the quality of the machining done by the manufacturer, the two systems should be indistinguishable from the profile. The key difference lies in the placement of the recoil grooves and with width of the grooves. MIL-STD-1913 (Picatinny) grooves are .206″ wide and have a center-to-center width of .394”. The placement of these grooves has to be consistent in order for it to be a true ‘Picatinny’MIL-STD system. Weaver systems have a .180” width of recoil groove and are not necessarily consistent in a center-to-center measurement from one groove to the next.

In many instances, a Weaver system has a specific application that it is machined for, so interchangeability is not necessarily an issue. A MIL-STD-1913 system must adhere to the specifications listed above in order for it to be considered MIL-STD, since the military desires uniformity in the recoil grooves to allow for different systems to be mounted on the weapon with no concern for compatibility.

Now, what does this mean to you? Boiled down, it means that accessories designed for a Weaver system will, in most cases, fit on a ‘Picatinny’ system. The reverse, however, is probably not the case. Due to the larger recoil groove, ‘Picatinny’ accessories will not fit a Weaver system. There are, of course, exceptions to every rule, but for a good rule-of-thumb, [full-width] ‘Picatinny’ won’t fit Weaver, but Weaver will fit ‘Picatinny’.”

Permalink Optics, Tech Tip 6 Comments »
April 12th, 2016

Bart Goes High-Tech: LabRadar at a Benchrest Match

Bart Sauter Ray Gross LabRadar Benchrest Review Chronograph Bench tripod

Bart Sauter of Barts Custom Bullets has acquired a LabRadar chronograph. He was curious to see how his loads performed in actual match conditions, so he brought his LabRadar to a match and set it up right on his benchtop. What he learned was quite surprising. For one thing, Bart found that tuning for the best accuracy (in the conditions), was NOT simply a matter of maintaining velocity. Read all about Bart’s experience in this AccurateShooter Forum Thread.

LabRadar Report by Bart Sauter

Bart posted: “I shot a short range NBRSA match [in March] with the LabRadar on the bench! The benches were quite close, but the LabRadar was able to pick up my shots even with the other guns going off very close to it. This is a pretty impressive piece of gear.”

It’s great for tuning. I can’t say for sure but what I saw with the PPC is that just maintaining a certain velocity will not keep the gun in tune.”

One Forum member asked: “Was the LabRadar able to pick up shots that far back (behind the muzzle) and to the side? What setting did you have it set at?”

Bart’s LabRadar unit had no trouble picking up shots when set on the bench, a bit behind the muzzle. In fact, Bart noted: “Yes it can go a long way back. At home I could get back up to around 8 feet and pick up the bullet. It’s more sensitive about the side distance. I had mine on level 4. You can be a lot farther behind the muzzle then advertised. You can also point it at your buddy’s target and get his velocity.”

Bart set his LabRadar to be triggered by the shot: “I had a tuner on the gun but no muzzle brake. [The Chrono] was set to be triggered by the sound of the gun. When you move back you have to play with the trigger level. I put mine on a tripod and was able to pick up projectiles 8 feet back, but from the side had to be within 18 inches.”

RAV battery pack Amazon.comLong-Life Battery Power
Powering the LabRadar at the range is not a problem. Bart used a portable battery pack that can power the LabRadar for a long time: “I bought a RavPower battery pack from Amazon.com. It was the most powerful compact cell phone charger they had and [it costs about $30.00]. It was able to run the LabRadar for two full days without recharging and still had juice.”

The LabRadar is a pretty expensive piece of kit, but there’s nothing else like it on the market. Bart notes: “The LabRadar itself is about $560.00. The stand is $29.95 for the bench mount and the padded carry case is $39.95. So you’re around $630.00 plus shipping.”

LabRadar Field Test by Ray Gross
Bart Sauter Ray Gross LabRadar Benchrest Review Chronograph Bench tripod

If you are considering purchasing a LabRadar Chronograph system, we strongly suggest you read the very thorough and informative LabRadar Review by Ray Gross, Captain of the USA F-TR team.

LabRadar Chronograph Bart Sauter

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April 9th, 2016

Tuning Your Sandbag Hardness — Tech Tip by Speedy

Over the years, noted gunsmith and a Benchrest Hall-of-Fame inductee Thomas ‘Speedy’ Gonzalez has learned a few things about “tuning” rear sandbags for best performance. On his Facebook page, Speedy recently discussed how sand bag fill levels (hard vs. soft) can affect accuracy. Speedy says you don’t want to have both your front and rear sandbags filled up ultra-hard. One or the other bag needs to have some “give” to provide a shock-absorbing function (and prevent stock jump).

SAND BAGS & HOW TO FILL THEM by Speedy Gonzalez

I was asked several times by competitors at the S.O.A. Matches and F-Class Nationals as to how I fill my sand bags for benchrest competition. Here is a copy of a reply I gave several years ago:

Back in the old days, about the time Fred Flintstone was still alive, I worked for Pat McMillan for free, from time to time to learn all his secrets. One day little Speedy was filling some new sand bags out behind Pat’s shop, stuffing them with more sand than Taco Bell put beans in their Burritos. When Pat stepped out the back door and inquired as to what in the hell was I doing packing them there bags the way I was.

I looked up at him with eyes like a kid with his hands in a cookie jar. My reply must have sounded like Homer Simpson “Doooh”. Finally I said “I don’t know, Boss. I just thought you were supposed to fill these babies up and go shoot. I got that ‘You dumb bastard look’ from Pat and I knew it was lecture time. This was what he told me:

You can not have two bags filled so hard that you gun bounces on them in the process of firing round at your target, especially if you have a rig with a very flexible stock. The bags must be set up in a manner for them to absorb the initial shock of the firing pin moving forward and igniting the primer. Then [they must] maintain their shape and absorb the second shock wave as well the rearward thrust and torque of the rifle. What happens to the rifle when this is not done? Well let me tell you. The rifles have a very bad tendency to jump and roll in the bags. This causes many of those wild, lost shots that one can’t explain.

Charles Huckaba, Ken Terrell, Larry Baggett, Ralph Stewart and some of us Texas shooters talk about this phenomena quite often. We have all agreed that:

  • 1: You can not have two hard bags [i.e. both front AND rear] in your set-up.
  • 2: Heavy sand magnifies these phenomena.
  • 3: If you are a bag squeezer, pack ears hard and leave bag pliable enough to squeeze for the movement required. You may pack front bag as hard as rules permit.
  • 4: Free recoil shooters pack both bags firm, but not so hard as to allow stock jump. Especially if you have a stock with a very flexible forearm.
  • 5: We use play-ground sand, also know as silica sand. I sift mine to get any large impurities out then mix it with 25% to 50% with Harts parakeet gravel to the desired hardness that I am looking for. The bird gravel keeps the sand from packing itself into that solid as a brick state.

Speaking of bricks — another thing that happens when shooters employ that heavy zircon sand is the ears form a low spot under them from recoil and then tend to rock back and forth with the rifle causing many low shots to crop up. Edgewood makes an Edgewood/Speedy rear bag specially reinforced under the ears to eliminate this scenario.

One last note –If you use the Cordura bags keep them sprayed with a good silicon spray or “Rain-Ex”. This keeps them from getting sticky. Hey guys, try that and see if it helps. — Speedy

P.S.: I do not like the solid double-stitched leather bottoms. While this seems like a good idea, I see more shooters have problems because of them. They tend to slide around the bench and or slide with the rifle on recoil. The standard Protektor with Cordura rabbit ears and an Otto ring bag with a Cordura front would be what I would suggest to the new shooter or one of the Edgewood / Speedy rear bags, these mimic the “Donut” and feature a ring of leather around the bottom circumference that keep the bottom from rocking on the bench or ground if that is where you reside these days…

Permalink New Product, Tech Tip 3 Comments »