Check out how the Brain Exploder converted a Snow Wolf Barrett M82 Airsoft Sniper Rifle to being an HPA-powered one with the Protech MKII HPA Drop-in Kit. This is a two-part video... "So the guys at Protech Airsoft reached out to me to help spread the word about their new product the MkII HPA Drop In Kit. This replaces the internals of a gearbox for an air powered system. I am not a huge fan of external source guns for me there has to a justification, either recoil or performance. So I suggested I use it in a wall hanging gun of mine the Snow Wolf M82, the gun is massive but less than impressive in its AEG form. So I purchased a ton of parts to turn it from just an oversized M4 into a true accurate airsoft replica."