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MSAR STG-556 vs AUG

I recently reviewed the new U.S. version of the Steyr AUG/A3. At the time I noted that Microtech Small Arms Research (MSAR), which has spent several years rolling out its “STG-556” AUG clone, would probably retain a pricing and innovation edge over Steyr. During the recession MSAR cut its wholesale price from above $1400 to $1050. Then, in just the last few weeks, MSAR dumped their entire inventory on distributors at even lower rates, allegedly because they are moving their operations from Bedford, Pennsylvania to Raleigh, North Carolina.

Since I was already thinking about getting another receiver or barrel, I couldn’t pass up an opportunity to get an entire bullpup carbine for under $1100. Following are observations on the fourth-generation STG-556 I purchased, shown here below my Steyr AUG/A3 USA.

I was struck by a number of small but clever improvements MSAR has made to the AUG design:

The MSAR 16″ barrel uses 1:8 rifling, which is sufficient to stabilize up to 77gr bullets. (The AUG only comes with 1:9 twist, which is marginal for bullets over 70gr.)
The MSAR is more than half a pound lighter than the AUG/A3.
The MSAR has quick-detach sling loops on both the receiver and the stock pin. (In contrast, the AUG’s front sling loop is held in by a coil pin so it cannot be easily removed when not in use. Its rear loop can be switched from side to side by removing the entire stock pin, but cannot be completely removed.)
The MSAR stock has two QD sling loop attachment points molded into the stock, underneath the pistol grip and under the toe.
The MSAR trigger pack actually locks into the stock. You have to press the bolt catch to release it. (The AUG’s trigger pack just falls out.)

The MSAR beats the Steyr not only on price but also with these design enhancements. The only two things the AUG has going for it are (1) the support and reputation of Steyr-Mannlicher, and (2) the fact that it has met the production and performance standards of many professional militaries for many decades.

Other observations:

A new MSAR is tighter than a new AUG in a several dimensions: You actually need the help of the recoil spring to get the receiver to pop out of the stock during disassembly. And magazines do not drop free when released unless nearly fully loaded.
The MSAR bolt locks open on an empty magazine, after which it can only be closed using the bolt catch just above the magazine release. In contrast, the AUG bolt can also be released using the slide-cocking handle.
The Gen-4 MSAR has no forward assist. The AUG’s slide-cocking handle can be used as a forward assist.
Sadly, like the AUG, the standard STG-556 barrels use metric muzzle threads, so you’ll have to buy an adapter to use your American suppressors.

Important notes when purchasing an STG:

MSAR’s fourth generation starts with serial number 6500. MSAR has manufactured at least five thousand Gen4 STG-556 guns.
Earlier STG-556 versions have a Stoner-style Forward Assist (“FA”) and some compatibility problems. Therefore I would avoid serial numbers lower than 6500.
Don’t confuse the STG-556 with MSAR’s STG-E4. The E4 is a Gen4 variant compatible with AR-15 magazines — quite like the Steyr NATO conversion I described previously. It comes with many more rail mounting positions and runs at least another $250.
The Gen4 STG-556 works with AUG magazines. (It also appears to work with Steyr’s NATO conversion kit, although I only confirmed that its receiver fits in mine; I haven’t test fired it.)
It ships from the factory with 5 MSAR magazines.
MSAR STG-556 magazines do not work with AUGs without some extra machining.

The Missing Subsonic .22LR Market

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Precision shooters know that keeping bullet speeds out of the transonic region preserves accuracy. The pressure dynamics around the sound barrier can upset a ballistically efficient bullet on its way to the target.

It turns out that the round nose and stubby heel of a typical .22LR bullet make it remarkably aerodynamic at subsonic speeds. Consequently, match-grade .22LR ammunition is typically designed to leave a rifle barrel under 1000fps.

Competitive rimfire shooters aren’t the only ones who have discovered advantages to subsonic ammunition. Anyone who fires a well suppressed gun will note that even if the muzzle blast is fully contained in the baffles of a silencer a supersonic bullet makes a significant amount of noise of its own: As it travels down range the supersonic pressure waves in its wake produce a “sonic crack.” Since .22LR cans are so light, cheap, and efficient, there are a lot of suppressor owners opting for subsonic ammunition to keep shooting sessions as quiet as possible.

Anyone who has pulled a subsonic .22 bullet has probably been surprised at how much empty space is in the case. It takes less than one grain of powder to propel the standard 40gr .22 lead bullet to the sound barrier. With all that extra room in the cartridge, why not add some more mass to the bullet? After all, holding all else equal, mass is your ballistic friend: It increases ballistic coefficient, which increases a bullet’s effective range by helping it retain velocity and resist atmospheric disturbances. Extra mass at the same speed also increases energy, which enhances terminal ballistics.

At some point you’re bound to notice a peculiar offering in the .22 marketplace: Silver boxes of Aguila-brand subsonic .22LR ammunition with some odd-looking 60gr bullets. Based on all of the preceding observations, you might justifiably exclaim, “Ah ha! There’s a great idea! I’ll put those in my rifle and enjoy all of the benefits of subsonic shooting for pennies a round, but with improved ballistics!”

And you would be right, except for one problem: Virtually every .22LR barrel is made with 1:16” rifling, and that is not adequate to reliably stabilize those longer 60gr lead bullets. In fact, I have looked long and hard to find anyone who makes a .22LR barrel with faster rifling that is also threaded to accept a suppressor. (The closest you can come is to buy an aftermarket specialty barrel from a place like Green Mountain, and then pay another $100 to get someone else to thread its muzzle. Or buy a .22LR conversion kit for a .223 rifle, many of which have 1:9 twist threaded barrels.)

Do some more research and you will also conclude that Aguila does not enjoy the most stellar reputation in rimfire ammunition. And yet they are the only company that makes .22LR bullets heavier than 50gr (and there are only a tiny number of other specialty loads heavier than the standard 40gr).

.22LR is by far the most popular consumer cartridge. Every .22LR shooter with a silencer, and many without, would love to be able to buy reliable and accurate 60gr+ bullets, as well as threaded barrels with sufficient twist rates to stabilize them.

So my open question to the firearms industry is: Where are the reputable bullet manufacturers selling cases of plinking, varmint, and match-grade 60gr .22LR ammunition? And where in the vast marketplace of .22LR guns and parts are the 1:12 twist .22LR barrels with threaded muzzles to shoot those bullets?

Steyr AUG NATO conversion

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You may have a big collection of AR-15 magazines. Or maybe you don’t want to spend upwards of $40 apiece to build a collection of Steyr magazines that will only work with your AUG. In either case the Steyr NATO stock is a welcome option. I bought a conversion kit, which consists of a modified stock and trigger pack (a.k.a. “hammer group”), from CDNN for $300.

Top: Original AUG stock, trigger pack, and magazine. Bottom: NATO conversion kit, shown with an L5 magazine.

Shown here (top) is the original AUG/A3 stock and trigger pack and (bottom) the NATO Conversion stock and trigger pack, with Lancer’s transparent L5 AR-15 magazine. Like all AUG stocks the NATO stock is molded with a bump on the top receiver end. To accommodate the A3 receiver’s extended top rail this stock bump has to be cut down — an operation I was able to complete in just a few minutes with the careful use of a belt sander.

The trigger packs are identical except for a spring-loaded tab on the AUG pack that locks into the rear of their proprietary magazine. Because AR-15 magazines are designed for side latches the NATO stock has several differences from the standard stock:

There is no bolt release. The only way to get the bolt forward after it locks back on an empty magazine is to use the cocking slide on the front of the gun.
Only the right-side trigger bar reaches all the way to the trigger pack. The other is cut off somewhere before the magazine well.
It has a magazine release button, which is actuated by the standard AUG mag release lever. The button is flush with the stock so it probably wasn’t designed to be used directly, but from a shooting posture it is easier to push than the lever behind the magazine.
It can’t be adapted to left-hand ejection. Where the standard stock has a rubber cover over a left-hand port the NATO stock is molded solid.

Top: AUG Magazine. Bottom: L5 magazine.

For comparison purposes I have used L5 magazines on the NATO conversion. These cost $13 vs. at least $39 for Steyr’s 30-round AUG magazines. The L5 plastic shell is much thinner than Steyr’s uniformly thick body, but it has metal feed lips and a rubber base to help it survive drops.

My NATO conversion kit had a sticky trigger in addition to an even heavier trigger spring than normal, resulting in a out-of-the-box trigger weight of over 12 pounds (in contrast to the standard AUG trigger of “only” 9 pounds)! Fortunately Steyr has agreed to look at this. I will post details on fixing and improving the trigger soon.

[Update: Steyr’s Alabama technical services group took just two weeks to fix this up beautifully. Now the stock’s trigger is smooth and the sear spring breaks right at 9 pounds. Of course, a 9-pound trigger is still nothing to brag about. See also my post on AUG and MSAR Trigger Improvements.]

Steyr AUG/A3 USA

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This is my Steyr AUG/A3 SA USA, with a NATO conversion kit (covered in this separate review), and sporting an EOTech 512 sight. The AUG/A3 is the latest version of an Austrian 5.56mm tactical bullpup carbine, first produced more than 30 years ago, that is used by police and military units around the world.

Bullpup firearms have always struck me as a great — even obvious — idea: After all, why cantilever the entire barrel and action forward of the trigger, using the foot or more of stock between the grip and butt for nothing more than a cheek rest? Moving the action behind the trigger gives a much more compact and balanced weapon for a given barrel length.

The NFA gives us an extra incentive to pursue bullpups: Since unregistered firearms with stocks have to carry barrels of at least 16″, a standard rifle design is going to far exceed the minimum overall length (from butt of the stock to end of the barrel) of 26″: An AR-15 with a 16″ barrel and a 12″ length-of-pull is 36″ long. The AUG, with the same barrel and length-of-pull, comes in at just over 28″.

Of course there are some complications in the execution. The most significant for autoloading guns is where to throw fired cases. The FN P90, a pistol-caliber bullpup PDW, can eject straight downward because its magazine sits on top of the gun. But when the magazine is inserted underneath the action that path is blocked. FN’s F2000 and Kel-Tec’s RFB actually eject the cases forward into a chute that eventually drops them in front of the gun’s body. Like the SA-80, TAR-21, and FAMAS (also military bullpup rifles, but ones that are not currently available in the U.S.), the AUG uses a conventional side-ejection action.

Some people are fazed by the fact that the ejection port is just opposite the shooter’s head when the gun is shouldered. Having already put a few hundred rounds through mine I can attest that you won’t even notice. A religious tactician might complain that this gun can’t be shot cross-shoulder. You definitely would not want to fire it from the left shoulder (unless you like eating hot brass) but when tactics require it the gun can be thrust forward and fired from the left-hand side — particularly effectively when equipped with a good holographic sight.

In 1989 the federal government decided to apply a provision of the GCA to ban the importation of a number of foreign-made “assault rifles,” including Steyr’s AUG. A few thousand AUGs that had been imported prior to that date became collector items that traded for $3-4k apiece. After the 1994 Assault Weapons Ban expired in 2004 two domestic companies began to develop AUG clones: TPD’s AXR and MSAR’s STG. Soon Steyr decided to join the action by teaming with Sabre Defense to assemble bona fide Steyr AUG’s domestically to serve the U.S. market. These began shipping in 2009 as the Steyr AUG/A3 SA USA to indicate that they are Semi-Auto A3 variants assembled in the USA. (Their serial numbers all include “USA.”) In September I discovered the price had fallen below $1900 so I promptly grabbed one at a gun show. The complete AUG USA package includes a chrome-lined 16″ 1:9 barrel, two magazines, a soft case, sling, and a cleaning kit that fits in the rear of the stock.

According to Steyr the majority of the AUG USA’s components are made in Austria. Of the 12 components made in the US the two major ones are the stock and the barrel assembly. All other parts are imported and undergo final assembly by Sabre Defense.

One unfortunate specification being preserved in the AUG USA is the European M13x1 muzzle threading. Ratworx sells a thread adaptor for the 1/2×28 threading used by suppressors here, and Steyr said they are also working on releasing one. I suggested to Steyr that they instead work on a 1:7 twist 16″ barrel with 1/2×28 threads for this market since most tactical shooters now prefer heavier bullets that require tighter rifling, and we would then have two reasons to buy a new barrel group!

The A3 variant comes with a nice main rail for sights and a small forward rail at 1:30, which would be great for a laser or light. One drawback of the main rail is that it sits awfully close to the charging handle (a.k.a. “cocking slide”). The manual repeatedly instructs the user to operate the slide with an upward-facing palm to avoid scraping knuckles against the corners of the rail. I simply capped my unused rails with low-profile rubber Falcon covers ($2/6″ from Botach) and this is no longer an issue.

The AUG features an ingenious modular design. With no tools it quickly breaks down into 5 component groups shown here: Barrel, receiver, bolt carrier, stock, and trigger pack. (The butt pad and stock pin have been removed from the stock group as part of the take-down procedure.)

I was always enamored of the AUG because it was a beautiful and clever bullpup, and I am even more drawn to it since I have sworn off direct gas impingement actions (because they’re too hard to keep as clean as I like my guns): The AUG uses a two-position gas piston, so all the carbon fouling is limited to a small regulator, piston, and spring next to the front handle on the barrel assembly.

About that trigger…

The AUG trigger is notoriously bad, with a typical out-of-the-box pull weight of 9 pounds! Contrary to some conjectures this is not a problem intrinsic to bullpup configurations. Having studied the trigger pack I don’t believe it is even a consequence of constructing the sear and hammer out of plastic(!), although that may be an impediment to achieving a truly match-grade trigger. Steyr has simply constructed this gun with a trigger spring far heavier than necessary. This is probably a holdover from their original two-stage select-fire trigger system, which uses a partial trigger pull to discharge a single shot and delivers full-auto bursts with the trigger pulled fully to the rear.

For semi-auto AUG’s the trigger spring can be safely and significantly lightened. But at present the only aftermarket part available to do so is the TriggerTamer: A patented plastic piece that replaces the rear tab on the trigger pack to engage the trigger spring at a slightly less compressed angle, resulting in a one-third reduction in trigger weight. [Update: See my post on AUG Trigger Improvements.]

Sight

With the combination of its compactness and heavy trigger the AUG is ideally suited to CQB or the emerging “Personal Defense Weapon” (PDW) roles. Given the difficulty of triggering precision shots I think a magnified optic would be poorly suited to this gun. The ideal sight is a holographic red-dot, which gives the shooter the widest field of view and greatest ease of sight acquisition because one’s head does not have to be aligned with the sight: If you can see the dot anywhere in the sight window, it’s covering the point of impact. I ponied up $350 for an EOTech 512 from Botach. This sight combines proven military ruggedness with my favorite red-dot reticle: A large 65 MOA circle for fast targeting and a 1 MOA center dot for more precise sighting. Many other red-dot sights have larger center dots, which cover too much of a target for precise shots at longer distances.

Current Market

With the Obama-fueled gun-buying spree winding down and the economy bottoming out gun inventories are starting to climb. Apparently Steyr is now releasing the A3 to distributors for $1750. Meanwhile MSAR has dropped the wholesale price on its STG to $1050. MSAR is also doing some clever things with their fourth-generation (“E4”) models, including standard NATO magazine compatibility and multiple calibers. Steyr will probably not be able to keep up with MSAR’s innovations because the AUG USA is a tiny portion of their business, and also because they are very wary of crossing any lines with the ATF.

Tactical Rifle: Ruger SR-556

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The last time I wrote about the AR-15 rifle platform my biggest design complaint was the Direct Gas Impingement (DGI) action. This has been a feature since the very first generation of the weapon adopted by the military over 45 years ago. DGI contributes to the platform’s simplicity and lightness, but also has some undesirable consequences: Every time the gun fires it blasts hot propellant gasses back into the bolt carrier, baking a layer of carbon onto everything in the receiver. Decades of military service have proven that well-made AR-15’s can withstand this abuse and continue to function reliably with just basic cleaning and lubrication. But for obsessive owners who like to keep their guns in more immaculate condition this dirty design can be quite irritating.

When I bought my first AR-15 following the 2004 expiration of the federal “Assault Weapons” Ban I openly wondered why no manufacturer had produced a piston-driven variant of the gun, especially given the huge market for America’s favorite tactical rifle. Since then I tracked the gradual emergence of AR-15 piston actions, first as retrofit kits, then as new uppers and complete guns. There was a great deal of concern about the long-term reliability of converted actions, mostly because the AR-15 bolt carrier wasn’t designed to be hammered with a piston, and its geometry seemed prone to an adverse effect called “bolt carrier tilt.” Some manufacturers, most notably LWRC, built a new action from scratch to mitigate these concerns. However LWRC’s piston uppers were always very hard to acquire, and even today they command huge premiums.

In mid 2009 Ruger entered the AR-15 market for the first time, and they did so with a proprietary piston action. The SR-556 now represents the best value in piston-driven AR-15s. I sold my old DGI AR-15 to somebody less fastidious than me and last month managed to pick up a new SR-556 for just under $1500.

The SR-556 comes standard with a number of desirable upgrades over basic AR-15s. Among them:

Full-length quad-rail handguards, so you can easily add as many accessories as you can carry.
Top-quality folding iron sights (by Troy Industries).
A comfortable pistol grip (by Hogue).
Chrome-plated bolt carrier assembly, so what little dirt does get into the action can easily be wiped off.

The piston system was executed superbly. Only the three pieces in the front two inches need to be removed for cleaning. The piston regulator has four positions. In the off position the action doesn’t cycle, essentially giving you a bolt-action gun. The first position (smallest gas opening) is suited to use with silencers, which sustain more backpressure on the action. The second position cycles the action reliably under normal conditions, and the largest opening can be used to compensate for weak ammunition, a very dirty gun, or other harsh conditions.

Shooting the gun for the first time was a pleasure. There were absolutely no malfuctions. Even after sustained firing the bolt was cool to the touch (though the barrel and gas vent area still got quite hot!). Long-term reliability on a new design may not be certain, but the fact that Ruger is comfortable enough to roll these out in quantity is reassuring. This should certainly outlast piston systems that use DGI bolt carriers with their separate gas key: The SR-556 carrier is machined from a single piece of steel with just a little hump over the main tube to take the impact of the piston.

Out of the box this is a very good gun, but it does have a few shortcomings:

Like all piston guns this is both front-heavy and heavier (just under 8 pounds) than comparable DGI AR-15s (typically closer to 7 pounds). Of course even professional users of the DGI M4s have found it beneficial to put a vertical grip on the front of their guns. I added a GripPod ($80 from Botach) and found this mitigates the imbalance nicely, in addition to deploying a handy bipod when desired.
The flash suppressor has uniform slots around its entire diameter. When shooting prone or on a table this causes some of the muzzle blast to kick up dust. Although closed-bottom flash suppressors require indexing to install, this should be a trivial factor to accommodate on a production line. So shame on Ruger for not equipping this with a closed-bottom flash suppressor!
The telescoping buttstock is a standard M4 style, which leaves a lot of play between the stock and the buffer tube. They should have just equipped it from the start with a Magpul CTR (shown in the photo above), for which I had to pay another $80. (To fit this gun be sure to get the mil-spec, not commercial size CTR!)
It doesn’t come with a front sling loop or swivel.

M25 and M62 .30 caliber Tracer Bullets

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As a new handloader I thought it would be fun to add tracers to my inventory. Tracer bullets that have been pulled from surplus military ammunition can be picked up for $15/100 at gun shows or online.

I bought one bag each of M25 and M62 tracers, but since I couldn’t find any detailed information about them online I decided to analyze them myself. Ten of each are shown here, M62’s on the left. Both tracer types are marked with an orange tip. (The black residue on the bottom of the bullets is the remnant of sealant used on military ammo and comes off after a spin in a vibratory cleaner.)

M62 tracers are designed for .308 (7.62x51mm NATO) rifles. Overall length is 1.33″, and they have a single .05″ cannelure which leaves a bearing length of roughly .60″.

M25 tracers were supposedly designed for .30-06 rifles. They are nearly identical to the M62’s except for a second cannelure that allows them to be crimped more deeply in a case. This photo shows whole and sectioned samples of M62, M25, and (for comparison) 168gr BTHP bullets.

I weighed the M62’s at about 143 grains and the M25’s at about 145 grains. On both bullets the base of the copper jacket is crimped around a 1 grain copper cup about .20″ in diameter. The cup is seated almost .1″ deep from the base of the bullet on M62’s, and slightly more shallow on the M25’s — .06-.08″ from the base, which could account for the extra weight on the M25’s given that the overall length on both is the same. Ahead of the cup, and behind the lead core, is .40″ of tracer compound with a dimple in the center, shown here.

The tracer compound is brittle and powdery, and weighs only about 10 grains. It burns with a bright red flame for about 4.5 seconds and (in static tests at least) leaves behind 3-4 grains of ash.

In order to help conceal a shooter’s location these tracers are designed to not fully light up for the first 100 yards of flight. At muzzle velocities over 3000fps that’s just a tenth of a second from firing to the appearance of the full flame. I did a number of tests to try to determine the tracer compound’s ignition temperature as well as the mechanism by which this delay is achieved, but was unable to get consistent results.

First I took a tiny amount of tracer powder and put it directly on a thin nichrome wire linked to a dimmer switch and a thermocouple. I slowly raised the temperature to 900F but nothing happened. I shut down and then rapidly hit the heater with full current and got an immediate ignition. In later tests I opened the back of a tracer and put the compound in direct contact with a thick copper wire heated to 800F and still got no ignition!

In an attempt to more accurately simulate the conditions of being pushed from behind by the hot gases in a firearm I took an intact bullet and anchored its base directly to the top of a copper wire, which I slowly heated with a propane torch. It reached 540F and after some time at that temperature the entire tracer pellet ignited and ejected out of the back of the bullet, pushing the bullet 5 feet into the air and leaving the copper cup still on the test stand. That’s not what’s supposed to happen either, but it does suggest a potential failure mode: If the tracer compound ignites from anything other than its base a shooter will see a red flash and then nothing as the compound leaves the bullet and burns much faster dispersed in the air. This also confirms (as did later tests) that the tracer compound provides negligible thrust — in this extreme case accelerating the bullet less than 10fps.

[Update: Though they don’t significantly propel the bullet, burning tracers do extend the bullet’s range. In a summary of BRL research on .50 caliber bullets Robert McCoy notes, “The tracer adds heat and mass flux into the wake, which raises the base pressure and lowers the base drag. For the APIT, M20 projectile, the tracer reduces the total zero-yaw drag coefficient by approximately 7 percent, at all speeds tested.”]

Fortunately, it’s not hard to get a proper ignition of these tracers: Hitting them briefly with a propane flame will reliably ignite them, as shown in this video. Here is a photo of three burned tracers along with two of the recovered base cups.

Why Don’t Cars Display Engine Performance Data?

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Most modern cars have engine control computers and sensors that can tell not only whether your current tank of fuel is contaminated but also whether you would benefit from higher-octane gasoline. Yet few (if any) cars readily communicate those data to the driver. Why not?

Many car engines are designed with higher compression ratios that require “premium” gasoline for optimal performance. These cars can still run on lower-grade fuel: They rely on knock sensors to detect the failure of low-octane fuel to resist detonation and can retard ignition timing to counteract it. However this timing adjustment reduces engine efficiency and power, so typically drivers want to avoid it. (Conversely, higher-octane gasolines are sometimes sold at such a premium to regular that their higher cost might outweigh the efficiency benefit to engines tuned for them.)

But gasoline octane rating is not the only factor that determines safe engine timing. Air density, which decreases with altitude and temperature, also affects detonation. Fuel that works great in summer or mountains may bog your car down in cold or sea-level conditions. Only your engine knows for sure whether it’s running optimally, or whether it would benefit from a bump in your fuel tank’s octane.

Apparently some aftermarket engine computer interface devices (e.g., the ScanGauge or the DashHawk) can allow a driver to monitor engine timing retardation in realtime. Ideally manufacturers should convert these data into useful dashboard information. Perhaps something like, “Your current fuel is handicapping the engine. Increase tank octane by 2 for optimal performance in current conditions.”

Primer Pocket Cleaners: Lee vs RCBS

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Cleaning primer pockets of fired cases is part of the ritual of preparing accurate, reliable reloads.

RCBS sells a $15 Primer Pocket Brush Combo (Part #9574) for this purpose, consisting of a threaded handle and two threaded stainless steel wire brushes for each primer pocket size. It is the first tool in the following photo:

The second tool shown is Lee’s $2 Primer Pocket Cleaner (Part #90101). It is just a small blued steel cylinder with a squared-off blade on one side for small primer pockets and on the other side for large ones.

The following picture shows eight large-primer cases. The left two have not been cleaned, showing the importance of this step of brass preparation. The top three were cleaned with two twists of the RCBS tool, and the bottom three with two twists of the Lee tool. I thought the RCBS would be more comfortable and easy to use, but after prepping a batch of brass I became much more concerned about what it was doing to my primer pockets: As you can see the steel brushes leave noticeable gouges in the brass. In contrast, the Lee tool keeps the pocket face square and relatively unscathed.

I can’t see any good coming of marring primer pockets to this degree. Especially over repeated uses the RCBS brush is removing measurable amounts of brass, and if you didn’t need it the first time it will almost certainly be needed on subsequent cleanings since the primer pocket floor is no longer flat enough for a tool like Lee’s to make full contact. Therefore I recommend against the RCBS tool. Lee’s much cheaper tool is a perfectly functional solution to primer pocket cleaning.

David Bookstaber

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