April 7th, 2019

Sierra Secrets — How MatchKings Are Made

Sierra Bullets Carroll Pilant MatchKing Bullet SMK Bullet-making Jacket

The Making of MatchKings — How Sierra Produces SMKs
All Sierra bullets begin life as a strip of gilding metal, an alloy consisting of 95% copper and 5% zinc. To meet Sierra’s strict quality requirements, the gilding metal requires three times more dimensional and quality control standards than is considered standard in the copper manufacturing industry.

A blanking press stamps out a uniform disc and forms the cup that will be drawn into the MatchKing jacket. The cup is then polished and sent to a draw press to be drawn into a jacket that is longer than needed for the future MatchKing, thus allowing for the trim process. Press operators constantly check concentricity to make sure we have only quality jackets. The jackets then go to a trimmer where they are visually inspected again.

Sierra Bullets Carroll Pilant MatchKing Bullet SMK Bullet-making Jacket

After being polished a second time, the jacket travels to the bullet press. In the meantime, 80-pound lead billets are being extruded into lead wire for the cores where great care is taken so that the core wire is not stretched. The core wire is lightly oiled before continuing to the bullet press to be swaged.

The lead core wire and trimmed jacket meet at the bullet press where the first stage forms a boattail on the jacket. The lead core is then formed on top of the bullet press and fed down into the jacket. In one stroke of the press, the MatchKing is formed.

Sierra Bullets Carroll Pilant MatchKing Bullet SMK Bullet-making Jacket

Quality control technicians pull samples from each lot of MatchKings to make sure they meet Sierra’s stringent standards. Samples are then sent to Sierra’s 300-meter underground test range (shown below) to be shot for accuracy on mechanical mounts referred to as “unrestricted return to battery rests” that Sierra designed and built in-house.

Sierra Underground Tunnel test facility Sedalia, Missouri

Sierra bullet sale Clarus Corporation

After inspection, the bullets are placed in the familiar green box along with reloading labels. They are then shrink-wrapped and shipped all over the world.

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April 6th, 2019

Primer Comparison Testing with 6 BRA at 500 Yards

primer 500 yard testing node vertical H4895 BRA

Here is a very interesting test for the 6 BRA (6mmBR Ackley) cartridge. Forum member James Phillips, a talented long-range benchrest shooter, tested SIX different primer types from three different manufacturers. To help determine vertical dispersion, James set his target out at 500 yards. He then proceeded to shoot 4-shot groups, in order, with each primer type. Velocities were recorded with a chrono. The photo above shows the results. James says: “I’ll retest the best two for accuracy and consistency with 10 shots each”. CLICK HERE for full-screen target photo.

Wheeler 6BR 6mmBR Ackley Improved James Phillips

As you can see, ALL the groups are pretty impressive. The smallest groups, 1.253″, was shot with CCI 400 primers. Next best (and very close) was CCI BR4, at 1.275″ for four shots. The “flat line” winner was the Remington 7.5, at upper left. There was almost no vertical. If you are intrigued by this interesting primer test, you can ask join the discussion in this Primer Test FORUM THREAD.

Primer Brand Group Size Velocity Extreme Spread Std Deviation
Remington 7.5 1.985″ 4 shot 2955 FPS 8 FPS 4.0 FPS
Federal 205M 2.200″ 4 shot 2951 FPS 11 FPS 4.8 FPS
Sellier Bellot SR 1.673″ 4 shot 2950 FPS 14 FPS 5.9 FPS
CCI 450M 2.341″ 4 shot 2947 FPS 14 FPS 6.6 FPS
CCI 400 1.253″ 4 shot 2950 FPS 3 FPS 1.3 FPS
CCI BR4 1.275″ 4 shot 2949 FPS 15 FPS 6.9 FPS

CARTRIDGE: 6mmBR Ackley, aka 6 BRA. Parent case is 6mmBR Norma. The 6 BRA is fire-formed to create a 40-degree shoulder and less body taper. Capacity is increased, but the neck is longer than a 6mm Dasher. The capacity is enough to get to the 2950+ FPS accuracy node. Some shooters say the 6 BRA is more forgiving than the 6mm Dasher. The 6 BRA is certainly easier to fire-form.

LOAD SPEC: 6 BRA (40° 6 BR Improved), 31.1 grains Hodgdon H4895, Bart’s 105gr “Hammer” bullets.

TEST REPORT — Conditions, Shooting Method, Loading Method

Tester James Phillips posted this report in our Shooters’ Forum:
Conditions: The testing was done in the morning over flags. The flags never moved or even twitched. I had as perfect conditions as I could have asked for. It was overcast so no mirage and no wind. There were no other shooters, just me.

Test Procedure: Each shot was precisely shot at my pace and centered the best possible using my Nightforce 15-55X scope. I did not use the round-robin method. Each four-shot group with the same was shot at one time. Then I moved onto the next primer. Everything felt right for each and every shot fired today. Of course I could repeat the test tomorrow and it could be exact opposite of today’s test. We can chase this forever. But [soon] I’m going to test the BR4 and 400 primer… for best accuracy and consistency for 10 shots each.

How Rounds Were Loaded: Each load was weighed to one (1) kernel of powder. So I know that’s as good as I can weigh them. Each bullet seating force was within 1# on my 21st Century hydraulic arbor press.

Previous Initial Load Testing: All groups were shot with 31.1 grains of H4895. During initial load testing I settled in on the Sellier & Bellot primer to finalize everything as it showed more promise over the CCI 450 Magnum I also tried. I was actually surprised to have seen the higher ES and SD from that primer today along with the vertical shown. [Editor: Look carefully — one shot from the CCI 450 is right in the center black diamond, stretching the vertical. By contrast the Rem 7.5 had almost no vertical.]

primer 500 yard testing node vertical H4895 BRA

Velocity and NODE Considerations: I was about 5-6 FPS above what appeared to been my optimum velocity of 2943-2945 FPS, so I’ll test 5 shots of 31.0 and 5 of 31.1 and see what happens from there. I can only assume my velocities where higher due to the higher humidity and of course temps were 5 degrees warmer this morning as well. It wasn’t far off but I noticed it.

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April 2nd, 2019

How 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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March 29th, 2019

Inspect Your Fired Brass to Avoid Catastrophic Case Failures

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing
Close-up view of a sectioned case. This one here was “fixin’ to pop”, says Glen Zediker.

Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In this article Glen focuses on cartridge brass. Glen discusses the most common failures that appear with brass that has been shot multiple times, or which has been fired at excessive pressures. Glen explains some simple ways to check your cartridge brass to detect “early warning signs” of case failure, particularly case head separation, which can be dangerous.

Glen is the author of many excellent books on reloading. This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com.

Handloading for Competition
by Glen Zediker

The Competitive AR-15
by Glen Zediker

Top-Grade Ammo
by Glen Zediker

How Cases Degrade with Multiple Firings By Glen Zediker
This article explains when, and then how, to check after the progress of changes commencing with the firing on a new case. It’s the “progress of degeneration,” in a way of looking at it because the concern is getting a handle on when enough change in the brass has come about to require attention. Or abandonment. As said then, for me that’s 4 firings. That, as said last time, is when I might see changes that need attention. Also as said, that figure didn’t come out of a hat, but from my own notes in running my competition NRA High Power Rifle loads. [Editor’s Note: With Lapua brass, using moderate loads, in bolt-action rifles, we typically get about 10 good (match-worthy) firings. But if you anneal your Lapua brass, and run modest pressures, Lapua brass can perform well for 20 or more load cycles.]

The areas most affected are the case neck and case head area. Case neck walls get thicker [but] the case head area body walls get thinner. Primer pockets get shallower and larger diameter.

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

This case shows a cracked neck AND a crack (separation) above the case head. Zediker says it is “rare to see one case with both of the most common failures. [This case] was attacked by an M14.”

Case Head — Causes of Separation and Cracking
When a case is under pressure during firing, the brass, like water, flows where it can, where it’s more free to move. Of course, the chamber steel limits the amount it can expand. The case shoulder blows fully forward and the case base is slammed back against the bolt face. There is, therefore and in effect, a tug on both ends — it gets stretched. The shoulder area is relatively free to expand to conform to the chamber, but the other end, the case head area, is not. Since that’s the area of the case with the thickest walls, it doesn’t expand “out” much at all. What it does is stretch. The “case head area,” as I refer to it here, is the portion of the case above the web, which is just above the taper that leads in to the extractor groove. The “area” extends approximately an eighth-inch up the case body.

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

Here’s a “pressure ring.” You’ll see this after firing, if you see it. And, if you see it, that case is done. The bright ring indicates excessive stretching, which indicates excessive thinning. If you see a ring circling the case, noticeable because it’s lighter color than the case body, and it’s in this area, I’d say that case is done. And that’s right where a “head separation” occurs. It can crack and also blow slap in two, and that’s the “separation” part of case head separation.

Case-head case cartridge pressure ring separation head failure GS Arizona
Photo courtesy GS Arizona.

This is a spot to keep close watch on as cases age. It is also the area that is more “protected” by sizing with less case shoulder set-back. That is, pretty much, where the freedom for the stretching movement in this area comes from (the case shoulder creates a gap). If you’re seeing a sign that a head separation [might happen with relatively few firings], chances are the shoulder set-back is excessive, and also… the load pressure level.

Bent Paper Clip Case-Wall Gauge
Case-Head Separation paper clip Glen Zediker GS Arizona

Editor: You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case.” Photo by GS Arizona.

Monitor Primer Pocket Dimensional Changes
Another case-head-area and pressure-related check is the primer pocket. As said, the primer pocket will get larger in diameter and shallower in depth each firing. As with many such things, the questions are “when” and “how much,” and the main thing, “how much?”

If the pocket gets excessively shallow, and that’s judged by a primer that seats fully but isn’t at least a tick below flush with the case base, there could be function issues. There’s a risk of a “slam-fire” with a semi-auto that uses a floating firing pin, and, if there is actual protrusion, that has the same effect as insufficient headspace. A primer pocket uniformer can reset the depth of a shallowed primer pocket to what it should be, but the real test for me is how easily the next primer seats into it. If it’s significantly less resistance, I’ll say that case is done. Shallower can be refurbished. That’s a primary function of a primer pocket uniformer. Larger diameter, though, can’t be fixed. I’ve mentioned in another article or two that, any more at least, my main gauge of load pressure has become how much primer pocket expansion there’s been.

AR15 Glen Zediker Practical AR-15 book newGlen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE!

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March 29th, 2019

Breath Better… To See Better (and Shoot Higher Scores)

Vision Eye Target Scope Relaxation Oxygen Target

Do you find that the crosshairs in your scope get blurry after a while, or that you experience eye strain during a match? This is normal, particularly as you get older. Focusing intensely on your target (through the scope or over iron sights) for an extended period of time can cause eye strain. Thankfully, there are things you can do to reduce eye fatigue. For one — breathe deeper to take in more oxygen. Secondly, give your eyes a break between shots, looking away from the scope or sights.

In our Forum there is an interesting thread about vision and eye fatigue. One Forum member observed: “I have noticed recently that if I linger on the target for too long the crosshairs begin to blur and the whole image gradually darkens as if a cloud passed over the sun. I do wear contacts and wonder if that’s the problem. Anyone else experienced this? — Tommy”

Forum members advised Tommy to relax and breath deep. Increase oxygen intake and also move the eyes off the target for a bit. Closing the eyes briefly between shots can also relieve eye strain. Tommy found this improved the situation.

Keith G. noted: “Make sure you are still breathing… [your condition] sounds similar to the symptoms of holding one’s breath.”

Phil H. explained: “Tom — Our eyes are tremendous oxygen hogs. What you are witnessing is caused by lack of oxygen. When this happens, get off the sights, stare at the grass (most people’s eyes find the color green relaxing), breath, then get back on the rifle. Working on your cardio can help immensely. Worked for me when I shot Palma. Those aperture sights were a bear! The better my cardio got the better and longer I could see. Same thing with scopes. Try it!”

Watercam concurred: “+1 on breathing. Take a long slow deep breath, exhale and break shot. Also make sure you take a moment to look at the horizon without looking through rifle or spotting scope once in a while to fight fatigue. Same thing happens when using iron sights.”

Arizona shooter Scott Harris offered this advice: “To some extent, [blurring vision] happens to anyone staring at something for a long time. I try to keep vision crisp by getting the shot off in a timely fashion or close the eyes briefly to refresh them. Also keep moisturized and protect against wind with wrap-around glasses”.

Breathing Better and Relaxing the Eyes Really Worked…
Tommy, the shooter with the eye problem, said his vision improved after he worked on his breathing and gave his eyes a rest between shots: “Thanks guys. These techniques shrunk my group just a bit and every little bit helps.”

Read more tips on reducing eye fatigue in our Forum Thread: That Vision Thing.

To avoid eye fatigue, take your eyes away from the scope between shots, and look at something nearby (or even close your eyes briefly). Also work on your breathing and don’t hold your breath too long — that robs your system of oxygen.

eye vision Vince Bottomley

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March 27th, 2019

USAMU Tips for Using a Progressive Reloading Press

Accurateshooter.com USAMU progressive press reloading

Each Wednesday, the U.S. Army Marksmanship Unit (USAMU) publishes a reloading “how-to” article on the USAMU Facebook page. In this article, the USAMU’s reloading gurus help you avoid potentially disastrous mistakes with a progressive — such as double powder changes. The USAMU experts caution that: “beginners would be better served by starting on a single-stage press”. That said, owning a progressive makes sense if you shoot more than 100 centerfire rounds a week. If you own a progressive press, or are thinking of buying one, you should read this article.

USAMU Reloading

For those interested in progressives, we’ll examine different key features among the types and relate them to handloading processes. The first, and simplest, type is the manually-advanced progressive. The shellplate holds the several cartridges being processed with each stroke of the handle. On these presses, the loader must manually advance the shellplate after each handle stroke.

While this obviously slows production vs. a press that cycles the shellplate automatically, this feature does have advantages though. (The disadvantages follow shortly.) No case is advanced to the next station until the operator deliberately does so – which is especially helpful for the new handloader.

Problems that arise during loading can be diagnosed and fixed without fears of some “extra” operation happening unnoticed with cartridges at the other stations. Beginners NOTE: one way to positively prevent this risk is to remove the cases from each press station when a problem emerges, before beginning diagnosis. Usually, however, experienced loaders omit this step as a time-saving measure, being confident in their understanding of the loading machine, process and the appropriate remedy.

Progressive press reloading ultimate reloader USAMU

If all cartridge cases are left in place, the operator must monitor what’s happening at each station. For example, raising the press ram twice may result in a double-charge of powder. With rifle cartridges, this usually results in a massive powder over-flow, alerting the loader to the problem. With pistol cases or small rifle charges in large cases, such an over-flow isn’t guaranteed. [Editor — one way to be sure you don’t have an overcharge or undercharge is to use a Lock-Out Die — see below.] The manually-advanced progressive keeps all operations under the loader’s control at all times. This is intuitively easier for the beginning loader to understand and to operate with confidence.

However, this same characteristic can be problematic if the loader isn’t paying 100% attention to what they are doing during routine operation. Some new handloaders apparently aspire to load progressively while daydreaming and paying little attention to the operation. Their plan is to feed components in, like feeding potato chips to a monkey, while good ammo drops out at the other end. Unfortunately, such an approach may likely result in something other than “good” ammo dropping out at the end…

Forgetting to cycle the shellplate when appropriate will cause problems. As with all handloading, distractions MUST be kept to a minimum for safety purposes. Never watch TV, talk with friends, or have other distractions (such as a rambunctious pet or child) in the room when loading. Avoiding distractions will do much to ensure that one produces consistent, high-quality ammunition, free of defects. For example, when a case doesn’t line up correctly with the case mouth expander or powder drop tube, a difference in “feel” often alerts the loader to correct the problem without ruining a case. If one is interrupted or becomes distracted, be certain to examine ALL cases in the shellplate before resuming loading.

Better Safe Than Sorry — the RCBS Lock-Out Die
RCBS Makes a “Lock-Out Die” that senses the powder charge. This will halt the Progressive press if you have a double charge, or an undercharge. Your Editor has the Lock-Out Die on his RCBS Pro 2000. It has “saved his bacon” a half-dozen times over the years. It can be used on Dillon and Hornady progressives as well as RCBS machines.

Other advantages of the typical manually-advanced progressives are that they are usually simpler in design, with fewer moving parts to get out of adjustment. This appeals to the mechanically dis-inclined! Caliber conversion kits are usually cheaper and take less time to install. This especially benefits the enthusiast who reloads for a wide variety of calibers.

However, many popular manually-advanced progressives have fewer die stations than the higher-end, auto-advancing machines. One item that is very useful when actually dispensing powder on a progressive press is a cartridge case powder-level sensor. This warns if powder levels in each case are too high or too low; however, it does require a die station of its own.

This condition (incorrect powder charges) often results from powder (especially extruded rifle powder) “bridging” in the powder measure. That is, one charge doesn’t fully empty into its cartridge case. This leaves some extra powder hanging up in the measure to join the normal charge in the next case. With some extruded powders, this can be quite obvious without a sensor. However, the sensor can detect small variations that would not be obvious to even an experienced, attentive operator. Considering the machine’s potential to use a powder sensor in addition to one’s other customary dies is a wise idea.

Similarly, pistol shooters are best served to seat bullets and crimp cartridges in separate operations. This should be taken into account when selecting a progressive press. Whenever loading fully-progressively, choosing powders that dispense very easily, e.g., ball/spherical or very fine-grain extruded powders, can help keep charges quite uniform.

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March 27th, 2019

Accuracy vs. Precision — Litz Explains the Difference

Applied Ballistics Rounds on Target DVD accurateshooter.com

The NSSF has posted a video featuring Bryan Litz of Applied Ballistics. Bryan also serves as Chief Ballistician for Berger Bullets and ABM Ammo. In this short video, Bryan explains the importance of ballistics for precision shooting at long range. Bryan covers key elements — drop, wind drift, angle correction and more. And Bryan also explains the key difference between Accuracy and Precision.

The principles Bryan discusses are covered (in greater detail) in the Putting Rounds on Target instructional DVD set. This 3-Disc collection boasts a total run-time of 3 hours and 37 minutes. The three DVDs, with many graphics and video segments, deliver as much information as a weekend shooting seminar… at a fraction of the cost. The 3-DVD set sells for $44.95.

Applied Ballistics Rounds on Target DVD accurateshooter.com

Disc 1

• Accuracy & Precision
• Tall Target Test
• Chronographs & Statistics
• Ballistic Coefficient
• Trajectory Terms
• Run Time: 1 hour, 4 min

Disc 2

• Primary Elevation (Wind)
• Secondary Effects
• Using Ballistics Solvers
• Short & LR Equipment
• Run Time: 1 hour, 11 min

Disc 3

• On The Range: .308 Win
• On The Range: .284 Win
• On The Range: .338 LM
• Extended Range Shooting
• One Mile Shooting
• Run Time: 1 hour, 22 min

DVD Applied Ballistics Bryan Litz Shooting F-Class .284 Win .338 LM

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March 26th, 2019

Safety Alert — Smith & Wesson 15-22 Rifle Bolt Issue

M&P Smith Wesson 15-22 Magpul cross training rimfire tactical

Smith & Wesson has issued a CONSUMER SAFETY ALERT for the M&P 15-22, a semi-auto .22LR rimfire rifle with ergonomics like the centerfire AR15. If you own an M&P 15-22, you need to inspect the bolt. A manufacturing problem with the bolt could allow the gun to fire when the bolt closes, even without pulling the trigger. This inspection process is described in this video.

Smith & Wesson states: “The bolt from your M&P 15-22 must be inspected to determine whether it exhibits the condition identified in this notice. To determine whether your firearm is affected by this condition, please inspect your firearm by following the inspection instructions provided here. We are asking consumers of all M&P 15-22 firearms manufactured before February 1, 2019 to inspect their bolt for this condition.”

M&P Smith Wesson 15-22 Magpul cross training rimfire tactical

Smith & Wesson Notice:
M&P 15-22 CONSUMER SAFETY ALERT
AND INSPECTION PROCEDURE

PRODUCT AFFECTED: ALL models of M&P15-22 rifles and pistols manufactured before February 1, 2019.

STOP USING YOUR M&P 15-22 UNTIL IT HAS BEEN INSPECTED AND YOUR BOLT REPLACED (IF NECESSARY).

Smith & Wesson has identified two M&P 15-22 firearms from recent production on which the breech face counter bore depth was not within manufacturing specification. In those firearms, the lack of depth may allow the bolt, upon closing, to crush the rim of the case, causing the round to fire, cycling the bolt, and potentially resulting in multiple discharges without depressing the trigger. This issue can occur in the following two scenarios:

1) With a loaded magazine in the firearm and the bolt locked to the rear, depressing the bolt release to allow the bolt to drop freely may ignite the round as the bolt closes without engaging the trigger and with the safety selector in either the safe or the fire position, and may also result in multiple discharges.

2) With a loaded magazine in the firearm, bolt in the closed position and a round in the chamber and the safety selector in the fire position, depressing the trigger will cause the round to fire normally, however as the bolt cycles, the next round may be ignited by the bolt crushing the rim of the case as it closes, causing multiple discharges.

We believe that these are isolated incidents, however, any unintended discharge of a firearm has the potential to cause injury. Therefore, we have developed this inspection procedure to ensure that all products in the field are safe to use. We are asking customers to perform the following procedure and to refrain from using their M&P15-22 until the bolt has been inspected and replaced as necessary.

REMEDY/ACTION TO BE TAKEN: The bolt from your M&P15-22 must be inspected to determine whether it exhibits the condition identified in this notice. To determine whether your firearm is affected by this condition, please inspect your firearm by following the inspection instructions provided here.

Safety Alert Tip from EdLongrange. We welcome reader submissions.

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March 26th, 2019

Sportsman’s Warehouse Now Offers Gunsmithing Services

sportsman's warehouse gunsmith smithing gunsmithing Utah mail chambering stock assemble

This is good news for gun-owners. Sportsman’s Warehouse (SW), which operates 92 retail stores in 23 states, now offers gunsmithing. Gun enthusiasts can get complete firearms gunsmithing services at the new Sportsman’s Warehouse Gunsmith Center in Utah. You can ship your rifles, pistols, or shotguns to the SW Gunsmith Center, or simply drop off your firearm at ANY Sportsman’s Warehouse store. The SW Gunsmith Center, equipped with mills and lathes, offers complete repair, refinishing, threading, metal, and stock work. For more info, visit: www.Sportsmans.com/gunsmith.

sportsman's warehouse gunsmith smithing gunsmithing Utah mail chambering stock assemble

“Customers can quickly and easily drop off their firearms directly at our new Gunsmith Service Center in Utah, take them to any Sportsman’s Warehouse store, or ship them in for service,” states Jon Barker, Sportsman’s Warehouse President/CEO. “Expanding from the Utah market, we now offer this unique service to customers nationwide, including our 92 store locations.” SW has a loyalty program — each dollar spent at the Gunsmith Center gives members a point towards earning SW gift cards.

sportsman's warehouse gunsmith smithing gunsmithing Utah mail chambering stock assemble

Fees Are Reasonable — $200 for Barrel Chambering
There is a $45 minimum charge for guns left overnight, and a $68/hour labor rate. A barrel chambering/fitting job costs $200. Threading a muzzle costs $100.00. Fitting an aftermarket AR trigger is $45. Blue-printing a bolt-action receiver costs $175.00. Glass-bedding an action costs $90-$175. CLICK HERE for Gunsmithing Fee Schedule.

sportsman's warehouse gunsmith smithing gunsmithing Utah mail chambering stock assembleThe new Sportsman’s Warehouse gunsmith shop is located in SW’s Salt Lake City Distribution Center. The workspace features four stations for gunsmiths to work on rifles, shotguns, pistols, and muzzleloaders. They also have added a full production lathe that is designed for 24-hour-a-day operation, as well as a large end mill for a variety of metal working operations.

Finish tanks, a spray booth and oven for Cerakote, along with other pieces of equipment that will allow them to perform almost any gun service or customization are being installed.

“The only thing we won’t offer is custom wood stock building,” said Bill Sturtevant, Head Gunsmith. “The time necessary for that service takes too much time and pulls our gunsmiths off of other projects for too long. But just about anything else, including refinishing stocks, is on the table.”

Sportsman’s Warehouse will offer 1-year and 3-Year Firearm Service Plans supported by the company’s gunsmiths. Plans include: mounting and bore sighting, field cleaning, factory-service augmentation, free shipping to the factory for repair, and discounts on Gunsmith Service Center work.

Story Tip from EdLongrange. We welcome reader submissions.

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March 23rd, 2019

Suppressor Facts Revealed — How They Work

Suppressor silencer NSSF infographic decibel noise reduction moderator fact sheet

Curious about suppressors (aka “silencers”, “moderators”, or “cans”)? Below you’ll find an informative NSSF Infographic that covers the history, legal status, design, and operation of modern-day suppressors.

Here’s a cool video showing how suppressors work. This video features see-through rifle suppressors filmed with ultra-high-speed (110,000 frame per second) cameras. When played back in super-slow-motion, you can see the flame propagate through the suppressor and the bullet move through each baffle before it exists the muzzle. Check it out!

See Through Suppressor in Super Slow Motion (110,000 fps) — Click Arrow to Watch:

Suppressor Facts — What You Need to Know

In this infographic, the NSSF provides the history, specifications, benefits and uses of firearm suppressors. Don’t suppress your knowledge!

Suppressors reduce gunfire sound levels by using baffles that contain expanding gasses exiting a firearm’s muzzle when ammo is discharged. Suppressors are similar to car mufflers that were, in fact, developed in parallel by the same inventor in the early 1900s. Well-designed suppressors typically reduce the gun sound levels by 30-35 decibels (dB). Suppressors are becoming more popular even though it still takes many months to get approved. In fact, the number of suppressors registered with the ATF grew by over 1 million from 2011 to 2017. That’s a 355% increase.

Suppressor silencer NSSF infographic decibel noise reduction moderator fact sheet

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March 22nd, 2019

Cantastic Video — How a Suppressor is Constructed

SilencerCo suppressor manufacturing production video Assembly

Watch this video to see how a sound suppressor (aka “silencer”, “moderator”, or “can”) is constructed, start to finish. It’s more complicated than you might expect — there are quite a few stages in the process. The video below shows the fabrication of a SilencerCo Octane 45 suppressor:

SilencerCo writes: “What, exactly, goes into making a silencer? It may be more than you’d expect. From cutting metal to chemical baths, to extensive quality control every step of the way, our streamlined process is more than just a few steps. Watch our newest video, HOW IT’S MADE: Octane 45, to catch a glimpse behind SilencerCo’s doors.”

SilencerCo suppressor
Photo courtesy UltimateReloader.com.

suppressor fact and fiction moderator silencer

How Loud Are Unsuppressed Rifles?
Firearms Are Loud — 140 dB to 175 dB. ASHA explains: “Almost all firearms create noise that is over the 140-dB level. Exposure to noise greater than 140 dB can permanently damage hearing. A small .22-caliber rifle can produce noise around 140 dB, while big-bore rifles and pistols can produce sound over 175 dB. Firing guns in a place where sounds can reverberate, or bounce off walls and other structures, can make noises louder and increase the risk of hearing loss. Also, adding muzzle brakes or other modifications can make the firearm louder. People who do not wear hearing protection while shooting can suffer a severe hearing loss with as little as one shot[.]” Source: ASHA, Recreational Firearm Noise Exposure.

How Much Does a Good Suppressor Really Reduce Firearm Sound Levels?
That depends on the rifle, the cartridge, and the effectiveness of the suppressor. American Hunter explains: “Suppressors retard the speed of propellant gases from the cartridge that rapidly expand and rush out of the barrel. It’s these gases that produce the loud boom that’s heard for miles. A suppressor’s series of internal baffles slows these gases so they are not all released at once, thereby muffling the sound.” Many good commercial suppressors can achieve 30-35 dB sound suppression. However, Zak Smith of Thunder Beast Arms says: “There are a bunch of manufacturers who publish values that are not reproducible, or use an ad-hoc test instead of a mil-spec test. In many cases we’ve tested the exact same suppressors they’ve advertised with 30-40 dB reductions and found they are actually in the high 20s instead.”

Again, for this reason, we recommend that hunters use ear protection, such as electronic muffs, even when shooting suppressed.

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March 19th, 2019

Gun Science: Engineers Plot Shots with Accelerometers

Texas Waterloo labs Youtube accelerometer gun .22 LR pistol test triangulation
A team of Texas engineers uses the principle of convolution to plot shot impacts. By triangulating data from multiple accelerometers, each shot’s exact point of impact can be plotted with great precision.

Waterloo Labs is a group of engineers from National Instruments and other self-declared “nerds” from Austin, Texas. These folks conducted an interesting demonstration using electronic accelerometers to plot bullet impacts from a suppressed Ruger MKIII .22LR pistol. The accelerometers respond to vibrations caused when the bullets hit a drywall target backer. By triangulating data from multiple accelerometers, each shot’s exact point of impact can be plotted with great precision. These point-of-impact coordinates are then fed into a computer and super-imposed into a Flash version of the Half-Life video game (which is projected on the drywall board). The end result is being able to “play” a video game with a real firearm.

triaxial accelerometerDo-It-Yourself Electronic Target System?
Now, we are NOT particularly interested in shooting Zombies in a video game. However, the technology has interesting potential applications for real shooters. Waterloo Labs has published the computer code, used to triangulate bullet impacts from multiple accelerometers. Potentially, a system like this could be built to provide display and scoring of long-range targets. Sophisticated electronic target systems already exist, but they use proprietary hardware and software, and they are very expensive. The Waterloo Labs experiment shows that shooters with some computer and electronic skills could build their own electronic scoring system, one that can be adapted to a variety of target sizes and materials.

In addition, we imagine this system could be utilized for military and law enforcement training. The walls of structures used for “live-fire” room-clearing exercises could be fitted with accelerometers so the bullet impacts could be plotted and studied. Then, later, the impact plots could be combined with a computer simulation so that trainees could “replay” their live-fire sessions, viewing the actual location of their hits (and misses).

Credit The Firearm Blog for finding this Waterloo Labs project.
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March 17th, 2019

Vihtavuori Explains Powder Grain Shapes

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

POWDER GRAIN SHAPES — What You Need to Know

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

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

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

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

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

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

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

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

Learn More with FREE Vihtavuori Reloading APP »

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


This article originally appeared on the Vihtavuori Website.

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March 16th, 2019

A Beauty of a Beast — .50 BMG Falling Block Rifle (Amazing)

.50 BMG J.T. 50-caliber Smith breech block falling block custom rifle
.50 BMG J.T. 50-caliber Smith breech block falling block custom rifle

This is one amazing .50-caliber rifle. Along with the lever-actuated falling block, it has a massive swing-out breech block like you’d find on a field artillery piece. The action is so wide that the sights and scope are offset. You’ve heard of the “Beauty and the Beast”? Well here the Beast IS a Beauty….

View looking down at the action from above. Note the hinged Breech-Block.
.50 BMG J.T. 50-caliber Smith breech block falling block custom rifle

This extraordinary example of gunsmithing art was crafted by the late J.T. (Jack) Smith of Sudbury, Massachusetts. This unique .50-caliber rifle features an aircraft machine gun barrel cut down to 38-1/4″, and turned octagon to round (in the style of Schuetzen rifles). The round portion of the barrel is tapered with a heavy boss at the muzzle. The barrel is inlaid in gold on both left and right side top flats. Custom scope bases are fitted to the receiver and to the top of the barrel. These hold an externally adjusting Unertl 15X target scope in offset scope mounts.

.50 BMG J.T. 50-caliber Smith breech block falling block custom rifle

Huge Falling Block Receiver
The massive receiver (8″ long x 2-3/4″ wide x 3″ deep) is remarkable in design and construction. Machined from solid steel, the action incorporates several unique features. Note the hinged Howitzer-style breech block which swings to the right and mortises into the back of the receiver in the loading slot, providing a back-up for the falling block. We’ve never seen anything like that on any rifle. The one-piece floorplate/lever incorporates a Ruger No. 1-style latch which locks into the bottom of the trigger guard. The entire floorplate and lever retract downward. Firing is accomplished by means of a striker mounted in the hinged (swing-out) breech block. This is manually cocked with another lever on top of the breech block. Dropping the falling block activates the extractor which removes the spent case.

Offset Sights
This rifle features a custom-built, windage-adjustable offset front sight plus a custom-built vernier tang sight with aperture offset to the left side. The sights are offset to the left for a right-handed shooter, to correct for the extreme width of the receiver, allowing a more comfortable head position.

.50 BMG J.T. 50-caliber Smith breech block falling block custom rifle

(more…)

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March 10th, 2019

Tall Target Test — How to Verify Your Scope’s True Click Values

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.

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March 5th, 2019

When ARs Fail — Busted Bolt Incident

AR15 AR-15 Bolt failure Broken AR Bolt Police Department

Our friend Dennis Santiago was recently conducting training for a Southern California Police Department. During a training session one of the unit’s AR15s stopped functioning. The problem — the bolt in the AR rifle broke in half. Dennis states: “They ran the gun dry, broke for lunch, shot it again. They don’t like that. I personally like to flood the bolt wet with lube on training days. It prevents stuff like this. Given that, it’s a simple remove-and-replace fix.”

AR15 AR-15 Bolt failure Broken AR Bolt Police Department

Here are some of the more interesting comments about this parts failure — an AR bolt that literally sheared in half:

“If I was a betting man [the steel] wasn’t made by Carpenter Steel. They are one of the few companies that use the correct [milspec-steel, C-158] called out on the drawing which they coincidentally developed. Most of the other companies that make [AR Bolts] use different steel with the same heat treat specification as what is called out which gives them the potential of being a little on the brittle side at the upper end of the tolerance. When it comes to the AR platform, bolts are probably the only part of the entire gun where I must admit to being a little bit of a brand snob.” David O’N.

[Editor’s Note: Actually Carpenter Steel does not make AR bolts. They are a steel supplier, and yes Carpenter did develop the original C-158 steel for AR bolts. Here is a contrary view, claiming that AISI 9310 Steel is actually stronger than milspec Carpenter C-158: 9310 Steel for AR Bolts.]

“Dry bolt and carrier shouldn’t cause that. Looks like a big pressure spike. What kind of ammo…?” Guy G.
Reply from Dennis: “55gr factory ammo.Piles of it.

“Is that the new two-piece bolt everyone’s been talking about LOL?” — Darren R.

“Let me guess…the PD called you in cause they didn’t know why it stopped going ‘pew pew’?” — Jim O.
Reply from Dennis: “I was there today for qualifications. It broke during the rifle phase. Simple enough to fish the bolt parts out of the action. The training didn’t miss a beat. I have an armory full of the things.”

Permalink Gunsmithing, Tactical, Tech Tip 14 Comments »
March 3rd, 2019

How Rimfire Ammo is Made — Federal and CCI Videos Show All

22 .22 Plinkster Youtube Video CCI Speer Rimfire Ammo Ammunition plant Lewiston Idaho

CCI and Federal Premium are both brands of Vista Outdoor. Most CCI rimfire is produced in Idaho, while other Federal-branded rimfire ammo is produced in Federal’s Anoka, Minnesota facilities. Here we feature videos from both CCI and Federal ammo plants. Watch and learn how rimfire ammo is made.

Field & Stream Tours Federal Ammo Plant in Minnesota
A reporter for Field & Stream recently got a chance to tour the Federal ammunition production facility in Anoka, Minnesota. This large plant produces both rimfire and centerfire ammunition. While touring the plant, the reporter was allowed to capture video showing the creation of .22 LR rounds from start to finish. This is a fascinating video, well worth watching.

Note to Viewers — After Starting Video, Click Speaker Icon to HEAR audio!

This revealing video shows all phases of .22 LR ammo production including cupping, drawing, annealing, washing, drying, head-stamping, priming, powder charging, bullet seating, crimping, waxing, inspection, and final packaging. We recommend you watch the video from start to finish. You’ll definitely learn some new things about rimfire ammo.

.22 LR Ammo Production in Idaho
Back in 2016, YouTuber 22Plinkster was able to tour the CCI Ammo plant in Lewiston, Idado. Here is the rimfire production video he produced.

The Manufacturing Process for .22 LR Rimfire Ammunition
Shooting Sports USA explains: “Rimfire cartridge cases are the oldest self-contained cartridge in existence, having been in continuous production since the mid-1850s. Rimfire cases are drawn from a thin piece of brass and formed with a hollow rim. A priming compound is then forced into the case using centrifugal force, where it is charged with powder and a bullet is seated in the mouth of the case. The case is then crimped around the bullet to ensure sufficient push and pull when the round is fired. When the firing pin strikes the thin brass rim of the case, the hollow rim is crushed and the primer is ignited.” Source: SSUSA.org 9/2/2017.

.22 LR ammunition photo
Photo courtesy BulkAmmo.com.

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February 26th, 2019

Range Kit Essentials — 12 Handy Items for Days at the Range

Range Kit Gear shellholder safety dozen essentials

The shooting season is now in full swing. When you head to the range you’ll want to be prepared. That means collecting all the gear you’ll need at the range. It’s easy to forget small, critical items, so we’ve provided a checklist of the small “extras” you should pack before you head out to the range. In addition to rifle, rests, ammo, targets, and cleaning gear, here are a dozen essentials you should include in your range bag.

Shell-Holder — If you don’t have calipers, you can use a shell-holder to check for excessive case expansion from hot loads. If a fired case doesn’t slip into the shell-holder easily, your load is definitely TOO HOT.

Extra Earplugs — Always use ear protection when shooting. We bring a 35mm film canister with extra sets of foam earplugs.

Hex Wrench or Screwdriver for action screws — Action screws can work loose with time. Always bring the appropriate hex wrench or screwdriver whenever you go to the range.

Small Wrench for Scope Rings — Check the tension of your scope base and ring fasteners before you go. Bring along a small Torx wrench for the ring screws (or other tool that fits your fasteners).

Normal and Under-sized Jags — It is often wise to use one-caliber undersize jags when applying solvent with cotton patches. You should have a couple sizes in your range kit.

Extra Batteries — Bring extra batteries for all your electronic gear — which can include chronograph, windmeter, digital camera, GPS etc.

Small Notebook and Pen or Pencil — Use the notebook to record chron data, log group sizes, and make notes about wind and weather conditions.

Adhesive dots — Bring a few sheets of adhesive dots (sold at office supply stores). Use small white or black dots as target pasters. Use larger red or orange dots as aiming points (target centers).

Folding Chair or Camp Stool — This comes in handy if you’re spotting for another shooter, or if you reload away from the firing line.

Water Bottle — You can’t shoot well if you’re dehydrated. Bring at least two quarts of water with you and keep a bottle at the bench.

Surveyors’ Tape and Wood Stakes — You can make inexpensive wind indicators using surveyors’ tape attached to the top of wood stakes.

Small Plastic Ruler — Use this to measure your group sizes. A transparent (see-through) ruler works best. Rulers are also useful for drawing lines on targets.

This list is not intended to be exclusive. There are many other items you may wish to include. Obviously bring safety glasses, and Sharpie-type pens are always handy to mark targets. We invite our readers to add other “essentials” to the list. The important thing is to plan ahead, packing your key items before you drive to the range.

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February 24th, 2019

Primer Pocket Rocket — Another Reason to Use Eye Protection

Primer Blown Gas defect winchester casehead

A few years back, Our friend Grant Guess had a “close encounter” with a bad primer. An apparently defective primer caused part of the casehead on one of his rounds to blow out. This, in turn, allowed high pressure gas to vent through the damaged primer pocket. Take a good look, boys and girls. This is yet another very good reason to wear safety glasses. The cartridge was a 6.5-06, handloaded in necked-down Winchester-headstamp .270 Win brass. Grant reports:

“I had a blow through between the primer and the primer pocket today. The action was really smoking and I got a face full of gas. This was a reasonably light charge. Thank God for safety glasses.

I should also mention that it appears there is a 3/64 hole that is halfway between the primer and the primer pocket. Like it burned a small jet hole through both of them.”

Could this happen to you? It just might. On seeing this damaged case, one of Grant’s Facebook friends, Chris D., observed: “Search the internet, you will see a lot of these pin hole ‘in the corner’ failures. Obviously Winchester has some issues with the LR primers.”

Careful Examination Reveals Apparent Primer Defect
After this incident, Grant examined the damaged case: “I pinned the flash hole and it is not over-sized or under-sized. The primer clearly has an area where it had a defect. At [50,000 CUP], it doesn’t take much of a defect to cause issues. There was a slight bit of pucker-factor on the next shot….”

Primer Blown Gas defect winchester casehead

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February 22nd, 2019

MV on the Box? Why You Still Need to Chron Factory Ammo

muzzle velocity applied Ballistics MV chronograph

Why You CANNOT Rely on the MV Printed on the Ammo Box!
When figuring out your come-ups with a ballistics solver or drop chart it’s “mission critical” to have an accurate muzzle velocity (MV). When shooting factory ammo, it’s tempting to use the manufacturer-provided MV which may be printed on the package. That’s not such a great idea says Bryan Litz of Applied Ballistics. Don’t rely on the MV on the box, Bryan advises — you should take out your chrono and run your own velocity tests. There are a number of reasons why the MV values on ammo packaging may be inaccurate. Below is a discussion of factory ammo MV from the Applied Ballistics Facebook Page.

Five Reasons You Cannot Trust the Velocity on a Box of Ammo:

1. You have no idea about the rifle used for the MV test.

2. You have no idea what atmospheric conditions were during testing, and yes it matters a lot.

3. You have no idea of the SD for the factory ammo, and how the manufacturer derived the MV from that SD. (Marketing plays a role here).

4. You have no idea of the precision and quality of chronograph(s) used for velocity testing.

5. You have no idea if the manufacturer used the raw velocity, or back-calculated the MV. The BC used to back track that data is also unknown.

1. The factory test rifle and your rifle are not the same. Aside from having a different chamber, and possibly barrel length some other things are important too like the barrel twist rate, and how much wear was in the barrel. Was it just recently cleaned, has it ever been cleaned? You simply don’t know anything about the rifle used in testing.

2. Temperature and Humidity conditions may be quite different (than during testing). Temperature has a physical effect on powder, which changes how it burns. Couple this with the fact that different powders can vary in temp-stability quite a bit. You just don’t know what the conditions at the time of testing were. Also a lot of factory ammunition is loaded with powder that is meter friendly. Meter friendly can often times be ball powder, which is less temperature stable than stick powder often times.

3. The ammo’s Standard Deviation (SD) is unknown. You will often notice that while MV is often listed on ammo packages, Standard Deviation (normally) is not. It is not uncommon for factory ammunition to have an SD of 18 or higher. Sometimes as high as 40+. As such is the nature of metering powder. With marketing in mind, did they pick the high, low, or average end of the SD? We really don’t know. You won’t either until you test it for yourself. For hand-loaded ammo, to be considered around 10 fps or less. Having a high SD is often the nature of metered powder and factory loads. The image below is from Modern Advancements in Long Range Shooting: Volume II.

muzzle velocity applied Ballistics MV chronograph

4. You don’t know how MV was measured. What chronograph system did the manufacturer use, and how did they back track to a muzzle velocity? A chronograph does not measure true velocity at the muzzle; it simply measures velocity at the location it is sitting. So you need to back-calculate the distance from the chrono to the end of the barrel. This calculation requires a semi-accurate BC. So whose BC was used to back track to the muzzle or did the manufacturer even do that? Did they simply print the numbers displayed by the chronograph? What kind of chronograph setup did they use? We know from our Lab Testing that not all chronographs are created equal. Without knowing what chronograph was used, you have no idea the quality of the measurement. See: Applied Ballistics Chronograph Chapter Excerpt.

5. The MV data may not be current. Does the manufacturer update that data for every lot? Or is it the same data from years ago? Some manufacturers rarely if ever re-test and update information. Some update it every lot (ABM Ammo is actually tested every single lot for 1% consistency). Without knowing this information, you could be using data for years ago.

CONCLUSION: Never use the printed MV off a box of ammo as anything more than a starting point, there are too many factors to account for. You must always either test for the MV with a chronograph, or use carefully obtained, live fire data. When you are using a Ballistic Solver such as the AB Apps or Devices integrated with AB, you need to know the MV to an accuracy down to 5 fps. The more reliable the MV number, the better your ballistics solutions.

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