Convert Your AR To Gas Piston Operation
One of the greatest limitations of the AR system is arguably its direct impingment gas operation. Piston operation offers milder recoil, greater reliability and much easier cleaning by preventing hot gases being blasted into the operating components, stripping them of lube and coating them in carbon and powder residue. One manufacturer, Osprey, claims that a gas piston operated rifle needs only 1:13 the cleaning and has 1:13 the stoppages of a direct impingement operated one. The only real disadvantage is that a piston system removes the ‘free-floating’ barrel, but in practise this only matters with rifles intended to give truly superlative accuracy such as DMRs. Ruger, Sig and Heckler and Koch have all gone for piston operating systems with their AR system rifles.
The Adams Arms gas piston conversion was one of the first on the market and is still one of the best. It differs from many in offering no less than three settings – one for normal use, one for use with a suppressor and one that cuts off all the gas for manual operation or the use of a .22 blowback adapter. This kit comes in pistol, carbine, medium and rifle length gas system versions and uses a short stroke piston system. The gas block supplied has a Picatinny rail on top to take clamp-on front sights.
The CMMG gas piston conversion is also a short stroke system similar to the Adams Arms one. The carrier has a recoil shoulder machined into the carrier rather than just screwed on as in some other kits. This kit uses a clamp on arrangement for its gas block. It re-uses your existing bolt assembly – just remove the gas rings as these are not required with a gas piston system. The piston is hard chromed for long life.
The Osprey gas piston conversion is markedly different from the other two in employing a gas cylinder that is kidney shaped and wrapped around the barrel under the hand guard. The greater surface area averages out pressure resulting in a smoother operation and the sights gettingg back on target faster. It is also a drop in kit that uses the weapon’s existing front sight tower or gas block and can be put on in under 5 minutes. Again this unit uses a recoil shoulder that is milled into the bolt carrier rather than a separate unit with the potential problems that could entail. All three of these conversions come complete with a new A2 style handguard that offers the necessary clearance.
HK (Heckler & Koch) versus Colt