Piston drive system
Cooler and Cleaner? This may be for you!
http://dailycaller.com/2014/06/25/6-facts-about-ar-15-gas-impingement-vs-piston/
Piston drive system
Cooler and Cleaner? This may be for you!
http://dailycaller.com/2014/06/25/6-facts-about-ar-15-gas-impingement-vs-piston/