The AR57 has a special bolt and "buffer". Both are heavier then bolt carrier and buffer in an AR-15. The AR-57 is a straight blowback design, not gas operated. It does require a buffer spring. This is my AR-57 pistol: The plastic "magazine" is the brass catcher. That requires cutting off the feed lips. . The one shown holds all 50 pieces of spent brass. The buffer shown is a M1S "pistol" buffer. It uses a standard AR-15 Carbine spring. The much shorter GSE pistol buffer will not work as the AR57's bolt is not bored out from the rear like the bolt carrier in an AR-15 is.
Linear Mode
