Adams Arms AR-15 Piston Conversion Kit

posted on October 26, 2010

Almost from day one in the jungles and rice paddies of Vietnam, the M16 assault rifle suffered from serious reliability issues that earned it a reputation it has never quite lived down. Though a number of improvements were made to the rifle almost immediately and further refinements over the past four decades have increased reliability of the Army's main infantry weapon, the common wisdom is the direct gas operating system of AR-15-based rifles remains suspect. The War on Terror's campaigns in the mountains of Afghanistan and deserts of Iraq have done little to erase this legacy.

Over the years, a number of challengers to the M16/M4 platform have arisen, and it's not coincidence that nearly all of them drop the impingement system—which blows hot fouling gas directly into the receiver—and replace it with a piston operating rod. The U.S. Special Operations Command selected the SCAR (SOF Combat Assault Rifle), a piston-driven rifle by FNH, to replace M4s and M16s. The new rifle will soon be deployed in combat with the 75th Ranger Regiment.

While nearly every black-rifle manufacturer is now offering a piston-powered AR (even Ruger!), the fact remains that nearly all tactical rifles in the hands of civilian and law enforcement shooters are direct-gas systems. Though not even the most hard-core competitive shooter or SWAT officer will ever put their rifle through the rigors of a dusty war zone, even the weekend plinker and tactical collector may want to consider upgrading to a piston AR.

One great option is the new AR15 Fix from Adams Arms. This kit is a retro-fit system installable by most gun owners on most AR-15 rifles and carbines. I recently had the opportunity to check one of these kits out for myself.

The AR15 Fix piston system replaces the direct gas operating system, but doesn't require any permanent modifications to the firearm. This is great news for gun owners who might be interested in switching to a piston AR but want to keep the option of upgrading to a new rifle in the future. The AR15 Fix can be pulled off the original gun and put on the new one, while the original can be turned back into a standard direct gas rifle easily enough.

Adams Arms advertises that the kit is installable by most gun owners with standard tools in a half-hour or less, and I had the chance to put this claim to the test by installing the AR15 Fix on my own carbine-length AR. Though I do some basic work on my guns, I'm certainly not an expert gunsmith. I believe I fairly represent a typical gun owner when it comes to technical knowledge and capability, and I was quite interested to see just how easy installation was for the Average Joe.

The biggest problem I had was, predictably, removing the original gas block/front sight of my rifle. I don't know how they drive those pins in there, but it took a fair amount of effort (and a smashed thumb) to get them out. After that hiccup, however, the rest of the process was a breeze.

The new Adams Arms gas block quickly mounted with hex screws and a new bolt carrier key, a couple springs and a bushing were all that was needed before adding the sleeved drive rod. Supplied front handguards mounted normally, and I was left going back over the installation manual, convinced that I must have missed something. It was that easy. Though it took me more than half an hour due to the troublesome factory gas block, this is certainly a task that can be accomplished by a moderately capable gun owner.

Installation of the kit, of course, is only the beginning of the story. The real proof is in how it shoots. So I was off to the range with a load of precious ammo and my newly piston-ized AR.

The first few rounds were slow, deliberate shots with careful inspection of the weapon between each one. All was well, so I let her rip. A number of brands all fed and fired smoothly, and though the barrel warmed quickly, the bolt and carrier—thanks to the gas being vented out the front of the weapon (and away from my face)—stayed relatively cool.

Adams Arms recommends only full-powered .223 Rem. or 5.56 mm NATO ammunition for reliable function, and everything I fired during testing fit the bill. However, I couldn't resist simulating what a lot of civilian shooters will do from time to time, particularly in these days of skyrocketing ammo prices, and I loaded a mag of lower-powered steel case Wolf rounds. I let them fly as fast as I could pull the trigger, and though my aim wasn't anything to write home about, the AR15 Fix chewed them up with no problem.

Adams Arms has got a great little kit here, and with the U.S. Special Forces switching to piston rifles, I suspect increasing public demand for similar guns is going to keep them busy for the foreseeable future.


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