H3 Buffer (5.0-5.4 oz)

The H3 buffer represents the heaviest standard carbine buffer option, weighing between 5.0 and 5.4 ounces to provide maximum bolt carrier deceleration in extremely overgassed configurations. Originally designed for large-bore AR cartridges like .458 SOCOM and .50 Beowulf that generate massive bolt velocities in carbine-length systems, the H3 has found a home in short-barreled suppressed rifles where backpressure reaches extreme levels. This buffer delivers the maximum mass available in a standard carbine package.

Internally, the H3 buffer contains three tungsten weights separated by neoprene discs, eliminating the steel weights found in lighter buffers. This all-tungsten construction maximizes density while maintaining the standard 3.25-inch carbine buffer length. The additional weight significantly slows bolt carrier velocity, reducing felt recoil and protecting components from the battering effects of excessive gas pressure. However, this increased mass requires careful system tuning to avoid reliability issues.

The H3 buffer is best reserved for specific applications where extreme overgassing cannot be addressed through gas system adjustment. Short-barreled rifles under 10.5 inches running suppressors full-time often benefit from H3 weights, as do systems with oversized gas ports that cannot be easily replaced. When paired with an adjustable gas block and enhanced buffer spring, the H3 creates a robust solution for taming the most violent gas systems. For standard 14.5-16 inch barrels with proper gas port sizing, the H3 is typically too heavy and may cause short-stroking.