Running The Rifle-
Caliber Handgun

They have become a staple on the American gun market — “handguns” built de novo upon an AR chassis introduced the American gun nerd to an entirely new genre of firearm. Combining rifle-grade power with handgun-sized portability, these testosterone-laden pistols are either the best or worst of both worlds.

The Pistol Stabilizing Brace (PSB) from SB Tactical revolutionized the industry. Approved by the BATF in several guises, the PSB attaches to the near end of a handgun and provides extra stability and support without changing the host gun’s pistol classification. However, the PSB brings along a few legal quirks. For a time you could carry a gun legally and then commit a felony when you lifted the same weapon to your shoulder. Thankfully this seems not to be the case any longer — “incidentally” — but the rules could change literally overnight.

An astute reader recently asked how effective these handguns-born-of-rifles might actually be in their virgin state. Intrigued by the idea, we set out to run a gun typical of the breed and assess its effectiveness. After trying several different firing techniques, burning a few bullets and counting the resulting holes, we reached some conclusions that would not withstand even the most cursory standards of scientific acumen. What the project lacked in technical rigor, however, it made up for in fun.

Practical Iron

For this test, I used the no-longer-manufactured SIG P516. Built around a standard Stoner-inspired AR upper and lower receiver, the SIG P516 sports a 7.5″ barrel underneath a gas piston-driven action for flawless reliability. The flattop upper accepts any standard optics. Three stubby lengths of Picatinny rail on the forearm are adequate for grips, lasers, and lights. Be forewarned, however, one of the many ridiculous quirks surrounding the 1934 National Firearms Act opines an angled foregrip on a handgun is legal whereas a vertical foregrip is not. Don’t try to understand it. Just embrace the horror.

As a result of this arcane bit of foolishness, we restricted our P516 forearm to a Magpul AFG (Angled Foregrip) adorned with some rough appliqué material from Talon grips for better purchase. We mounted a SureFire X400 combination light and laser for use indoors or when the sun goes down. We perched a Holosun red dot sight atop the upper.

Holosun sights combine a ruggedized solar cell along with a battery backup for a robust red dot sighting solution taking up minimal space and remains all but weightless. The Holosun sight automatically adjusts its intensity for ambient conditions. This means if you chase something from the outside to the inside or vice versa, you need not call a timeout to fart with your optics.

In keeping with the original design of the AR pistol, we left the buffer tube naked. The point of this exercise was to run the gun in its native state without any ancillary stabilizing contrivances, though virtually all factory guns sport some variety or flavor of PSB. The results were illuminating.

Practical Impressions

Original M16 barrels are 20″ long while the M4 tubes most of our grunts are running downrange in the ongoing kinetic festivities overseas are 14.5″. The HK 416 rifle, which sent Osama bin Laden to his eternal reward in the hands of an American Navy SEAL, sported an 11″ barrel behind a sound suppressor.

The lightweight 5.56x45mm round was controversial when it was first introduced and it remains controversial today. The subsequent, occasionally acrimonious discourse has already spilt an ocean of ink. The issue is the tiny .22-caliber bullet this round pushes requires speed to be effective. Ranging in weights from 40 grains all the way up to 77, this little projectile better lends itself to use against squirrels than Homo sapiens when its velocity drops unduly. Chopping barrels undeniably amps up the cool points but only at the expense of velocity and subsequent effectiveness.

I love a good Hollywood muzzle flash as much as the next archetypal American male, but touching off one of these stubby little guns for real, particularly in dim light, can indeed both trash your night vision and make you a target. One poor unfortunate about whom I recently read was gunned down on the streets of Tombstone, Ariz. in the 1880s at extremely close range. In addition to having his mortal glow suddenly and violently snuffed, he had his suit jacket set afire by the muzzle blast of his opponent’s handgun. In the case of the P516, however, the standard M4 flash suppressor does a remarkably good job of ameliorating muzzle flash. If you doubt my assertion simply twist the device off with a wrench and launch a few rounds downrange at dusk. Don’t forget your sunglasses.

Practical Positions

We opted for four different shooting positions from which to deduce our assessment. We also fired my favorite Rock Island Armory .22 TCM 1911 alongside the P516 as a control. This gave us a yardstick against which to judge the P516, and the holes were the same size. We fired all courses offhand unsupported at a brisk cadence.

The first iteration involved running the gun off a single-point sling with the arms outstretched. This technique was pioneered in the HK MP5K machine pistol and offers both stability and maneuverability. Maintaining counter pressure on the sling helps balance recoil and the gun launches rounds naturally in the direction your arms point. This firing position also allows ready access to the optics.

Drawing the weapon up such that the buffer tube rides along the cheek looks lame but actually renders surprising accuracy. This position offers a stable firing foundation along with access to the weapon’s sights in a manner somewhat akin to what the gun’s original designers intended. Firing in this manner at 10 meters, we tore a jagged hole. While such stuff is made possible by the trivial recoil impulse of the 5.56mm round, I would be reticent to give it a whirl with a more powerful firearm. Such antics with a .308 could result in an introduction to a facial surgeon.

The isosceles stance drives much modern tactical shooting. In these days of ubiquitous body armor, this position also offers a good defense against hostile gunfire. The isosceles position with the body square to the target and both hands outstretched offers pretty fair stability even for a hefty handgun. However, the gun does get heavy fairly quick.

Just for giggles we also fired the gun sideways “gangsta” style. Limitations of the language preclude my adequately describing how comically stupid this is. I have been shot at once before. Suffice it to say if ever I am subjected to such unpleasantness again I sincerely hope the miscreants on the other end practice this particular proclivity.

Practical Reality

Though the handgun section of your local gun emporium is invariably the first stop for an American gun novice in search of an entry-level defensive weapon, the sad reality is handguns are the most difficult of all firearms to shoot safely and well. The ideal defensive piece for the inexperienced shooter is the pistol-caliber submachine gun. However, these handy little weapons are out of most civilian hands but in these handguns-birthed-of-rifles we do see some positive vestiges of the subgun.

Such weapons can indeed make fine defensive tools. Muzzle flash and sheer unfiltered noise are certainly considerations, particularly if these guns are used indoors or, Lord help you, touched off within a confined space like a vehicle. Their sinister visual signature along with the capacity to accept accessories like optical sights, lights, lasers and standard capacity magazines offer tactical capabilities not found on your favorite conventional service pistol. A turbocharged handgun like the SIG P516 might not be the first choice for a concealed carry weapon but should the zombies come — and you know they will — our bit of pseudo-science showed the P516 to be remarkably effective with all three of our legitimate shooting positions.

Burn enough ammo to get comfortable with your gun and practice to find what technique works best for you. During our recent testing we found our P516 grouped tighter than our favorite conventional handgun. It seems a rifle caliber handgun can indeed make for an effective defensive weapon.

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