Category Archives: Arms

Heavy Metals for Bullets

As a preface to an upcoming series on subsonic rifles, I have compiled the following information regarding metals for bullets.

To produce good ballistics a bullet needs several characteristics.

Internal: It has to remain solid at the temperature and pressures of firing, to avoid melting in the gun. It also must be softer than the barrel through which it is fired so that it conforms to the rifling of the barrel (which is critical to ballistic stability) and so that the barrel can be shot repeatedly without degrading.
External: It should be as dense as possible, since density not only increases stability but also reduces the energy lost to air resistance during flight.
Terminal: It needs to be tailored for some terminal objective. Depending on the target, we may want a bullet to explode, expand, penetrate, stop, or do some combination of those things.

Following is a list of elements that are of interest in meeting these objectives, ordered by density and noting their rough current cost:
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Sight in your Suppressor

Shooting the Short-Barreled XCR

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I spent some time at the range with a chronograph, my short-barreled XCR, and my newest 5.56mm suppressor: HTG’s Eureka-4. The Eureka is 4.6″ long and weighs only 15 ounces. It extends the gun’s overall length only 2.8″ more than the standard flash suppressor it replaces, making it ideal for a compact, CQB-style carbine like this.

George Vais, who patented and developed the HTG suppressors, assured me that the Eureka is designed to absorb the higher muzzle pressures of shortened 5.56mm barrels, which some people fear will erode the blast baffles of cans not designed for that abuse. Granted, my 11″ barrel isn’t remarkably short given that some people run these rounds through 7.5″ barrels. At 11″ even the standard flash suppressor does a decent job moderating the muzzle blast, so shooting this XCR is no harsher than any other carbine I have shot in this caliber.

With the silencer attached, the gas piston valve can be turned to its lowest setting (“S”) and the gun still cycles reliably. This is thanks to the longer backpressure curve that a silencer maintains. However, a consequence of putting rounds designed for 20″ barrels through a system this short is that a significant amount of propellant gas blows back through the ejection port, which is not the most pleasant thing to have venting in front of your face. If I had to do this all day I’d probably wear goggles to keep it from irritating my eyes.

Without the suppressor mounted I turn the gas valve to its highest setting (“4”), as is suggested during the first few-hundred round “break-in” period. Factory 55gr .223 loads that chronograph 3150fps out of my 24″ bolt gun leave the unsuppressed 11″ barrel at just over 2600fps. I was surprised to discover that the gun’s action can tap a lot of power out of the shots, even though with this barrel the propellant doesn’t reach the gas hole until 1.5″ from the muzzle: Turning the gas system from “4” to off — essentially making this a bolt-action gun — the bullets gain an extra 250fps! (Of course, this extra velocity is accompanied by a more violent muzzle blast.)

Screwing the silencer on increases muzzle velocity even further (thanks to an effect known as “freebore boost“): With the gas system off and the silencer on this gun shoots factory 55gr bullets over 2930fps, which is not bad for a barrel assembly measuring just 14” long overall. Turning the gas system back on to “S” drops velocity just below 2900fps. Out of curiosity I kept the silencer on and stepped the gas valve up a notch to “1,” which pounded the action harder, ejected the case further, and dropped muzzle velocity to 2830fps. Always one to test the limits, I then cranked the gas back up to “4” and fired one round, at which point the action crushed the neck of the spent case and somehow produced a triple-feed malfunction!

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Ammunition Prices

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Via The Firearm Blog, spot prices for the metals used in ammunition (primarily copper, lead, and zinc) are approaching their 2008 records and the Economist reports that they are projected to stay high.

Granted, the price of ammunition over the last few years initially shot up not because of inflation in the cost of raw materials but rather because of a massive increase in demand: U.S. military operations were already straining production capacity when political panic following the 2008 election prompted civilian stockpiling. Manufacturers are only now beginning to catch up to the demand.

I had hoped that at this point prices would begin to fall back towards the levels we saw in the middle of the decade. But now it looks like raw material prices may keep the floor close to where we are right now.

Robinson Armament XCR Short-barreled Rifle

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The Robinson Armament XCR is a “modular weapon system” that was originally developed as a candidate for the USSOCOM SCAR program. Of course, FN Herstel won that government contract and just last year began marketing civilian variants of its SCAR rifle. Robinson, meanwhile, shifted its attention to the civilian market where it began selling the XCR in 2006. Even with the recent introduction of the Remington (formerly Bushmaster) ACR the XCR is still the most widely available and, at around $1600, reasonably priced SCAR-type civilian rifle. It sports the following features common to this type of firearm:

Adjustable gas piston operating system
Foldable stock
Quick-change barrel
Multiple-caliber conversion
Monolithic upper receiver and rail system
Ambidextrous, short-throw safety

An excellent comparison with other “third generation carbines” is maintained on this chart.

Features unique to the XCR include:

Clever (and now patented) ambidextrous bolt catch, positioned just in front of the trigger guard.
Excellent 3.5-pound trigger. This “enhanced trigger” was introduced in 2009, about the same time as their ambidextrous safety, and replaces the 6 pound trigger found in earlier versions.
AR-15 compatible grip (the one shown here is the MagPul MIAD)
Non-reciprocating charging handle
3-lug bolt (easier to clean)

Features currently lacking on the XCR include:

Stock with adjustable length-of-pull and cheek height — although an “enhanced stock” is supposedly in development, and an optional adaptor allows any AR-15 stock to be installed.
Ambidextrous magazine release (“in development”)
Ambidextrous charging handle
1/9″ twist barrels are standard; 1/7″ to this point have been promised but hard to get.

A good critical review here summarizes common complaints about the XCR, most of which center on the fact that a lot of its hardware is screwed down instead of pinned. The XCR manual comes with a number of recommended points for applying red and blue loctite to keep screws in place.

In my opinion the XCR lower receiver is the ideal item to register as a Short-Barreled Rifle (SBR): The same XCR-L lower can then be fitted with uppers and barrels as short as 7.5″ as well as at least 3 caliber conversion kits (currently available: 5.56, 6.8SPC, and 7.62×39). The photos here show a standard 5.56mm upper with an 11″ barrel, which makes it 30.5″ long overall, and only 22.5″ with the stock folded.

A few other noteworthy details:

The gas system has six positions: Off, suppressor, and standard settings numbered 1-4.
The folding stock includes a quick-detach sling swivel slot for a single-point sling.
Company representatives frequent the official online forum.
The company has been responsive to my problems and requests via both phone and Email.

Products I’m looking for in 2010

Consumer High Speed Video Cameras

It has been more than a year since Casio began shipping the EX-F1, and it is still the fastest consumer video camera on the market. However, at its top speed of 1200 frames per second it only captures a very coarse 336 x 96 resolution.

Memory bandwidth and data buffering have previously been the bottleneck of high-speed video. Pros pay tens of thousands of dollars for specialty camera systems capable of capturing high-resolution video up to 10,000fps. (Higher frame rates require lighting power that would be beyond the means of amateurs.) But now that high-capacity solid-state data drives with write speeds over 500MB/sec are shipping for just a few hundred dollars the technology exists to produce a sub-$1000 consumer video camera that can capture full-resolution video at thousands of frames per second. I can’t wait to get my hands on one.

Better Console Gaming Controllers

Ten years ago Microsoft introduced a radical new gaming controller under its Sidewinder line called the Dual Strike. Apparently nine years ago they took it out of production. I used it to play several PC versions of Grand Theft Auto and liked the controller so much that when I discovered it was discontinued I scooped up a few more boxes at clearance. The Dual Strike is the best first-person shooter (“FPS”) controller I have ever used: It combines the precision and speed of a mouse with the convenience of a single hand-held gamepad that doesn’t tie you to a flat surface.

I recently picked up a PS3 and was excited to check out the state-of-the-art in FPS games. What I can’t believe is how bad the standard console controllers are for this purpose. Apparently people who are serious about these games buy split controllers like the FragFX which basically put you back at a desk with a mouse. Not exactly the setup one is looking for when plugging a console into a home theater system and sitting back on a sofa.

Though stockpiles of Dual Strike controllers are still available they are not compatible with the current crop of gaming consoles. I hope it’s not long before the console gaming complex rolls out a FPS controller to meet this need.

Computerized Ballistic Optics

Given how cheap and compact computer power is I can’t understand why the $1500 Barrett BORS is the only integrated ballistic computer on the market. Of course a professional shooter can do ballistics in his head for any shot one could take with a man-portable firearm (i.e., up to .50BMG shooting up to 1.5 miles). And serious amateurs cobble together their own ballistic computers, typically using a combination of smart-phone ballistics applications, Kestrel weather meters, laser rangefinders, and perhaps some angle gauges. Hopefully this is the year that scope or laser rangefinder manufacturers begin to integrate atmosphere and angle sensors along with ballistic data to provide precise firing solutions, perhaps even automatically adjusting the scope’s reticle for a particular shot. Before long I also hope to see laser rangefinders that integrate laser doppler anemometers to determine average windspeed and direction over the ballistic trajectory, making first-shot hits as precise as the rifle and the shooter’s trigger finger.

Bullpup Single and Double Rifles

As a fan of bullpup firearms I was excited by Steinkamp’s SW1 double rifle. But since their pricing is over the top I’m hoping that this year some domestic manufacturers will pick up on the concept to produce single or double bullpup rifles and shotguns.

Subsonic .22LR Ammunition and Barrels

As I wrote late last year, there are significant benefits to be had with heavier subsonic .22LR ammunition. I hope ammunition manufacturers step up their offerings of .22LR over 40 grains, and that .22LR barrel manufacturers switch to the higher twist-rates needed to shoot the stuff well.

MSAR STG-556 vs AUG

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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.

David Bookstaber

special interests