Editing Direct impingement (section)

== Advantages ==
Firearms with a direct impingement design can, in principle, be constructed lighter than piston-operated designs. Because high-pressure gas acts directly upon the bolt and carrier in a direct impingement system, it does not need a separate gas cylinder, piston, and operating rod assembly of a conventional piston-operated system, only requiring a gas tube to channel gas from the barrel back towards the action. This saves weight, lowers manufacturing costs, and reduces the mass of the operating parts, and thereby the wear on mechanical parts due to movement. By removing the gas piston, the potential amount of moving mass is also lowered, decreasing the potential for firearm movement and barrel distortion before the bullet leaves the barrel.<ref name=web>{{cite web |url=https://gundigest.com/tactical/ar-15-pistons |title=AR-15: Direct Impingement Vs Gas Piston |last=Sweeney |first=Patrick |publisher=[[Gun Digest]] |accessdate=9 August 2021 }}</ref>

The gas directed at the bolt carrier group may improve reliability in some conditions. The jet of gas can blow debris away from the ejection port which, in other designs, could enter the mechanism and foul the gun.