Heavy buffers are sometimes needed on short barreled AR-15 rifles or to smooth out operation on certain guns. H2 buffers are standard issue on US M4 Carbines. Select from H1, H2 or H3 buffers. Mfg: Brownells H1 - 3.8 oz, H2 - 4.8oz, H3 - 5.4oz
Brownells