||The H2 buffer adds needed weight to the reciprocating mass to ensure reliable performance with the 300BLK SBR, as well as 5.56NATO rifles.
The H2 buffer is a heavier buffer that replaces your standard buffer for reliable performance out of your 9” or 12.5” 300BLK. The standard buffer in an AR-15 Carbine is 2.9oz and intended for use with a mid/rifle length gas system. When you move to a carbine length gas system an H-buffer weighing 3.8oz is used. Because the gas system in the 300BLK 9” and 12.5” is a pistol length gas system, a heavier buffer is used for better performance.