What Are the Specs of the AR-15 Carbine Buffer Weights by Generic / Industry Standard?

How This Affects Your Build

Buffer weight directly controls your bolt carrier velocity and cycling reliability. Heavier buffers slow down the bolt and help tame over-gassed rifles, while lighter buffers can assist under-gassed setups. Getting the right buffer weight prevents bolt bounce, premature wear, and cycling issues that plague poorly tuned carbine systems.

The Detail

The industry standard carbine buffer weighs 3.0 oz total and contains one steel weight. This is your baseline buffer that works adequately in most standard carbine configurations with proper gas port sizing.

The H buffer steps up to 3.8 oz using one tungsten weight paired with two steel weights. The tungsten weights are significantly denser than steel, allowing more mass in the same physical space inside the buffer tube.

H2 buffers jump to 4.6 oz using two tungsten weights and one steel weight. Some manufacturers list this as 4.6 to 4.7 oz due to manufacturing tolerances, but 4.6 oz is the most commonly cited specification across the industry.

The heaviest standard option is the H3 at 5.4 oz, which uses three tungsten weights for maximum mass. This configuration works well with rifles that have oversized gas ports or shorter barrels that tend to be over-gassed.

Heavier buffers slow bolt velocity and reduce the violent rearward motion that can cause reliability issues in over-gassed rifles. Lighter buffers help under-gassed setups by reducing the resistance the bolt carrier group faces during cycling.

Build Impact

You need to verify specs with your specific buffer manufacturer since tolerances vary slightly between brands. Start with the standard 3.0 oz buffer and move up in weight if you experience harsh ejection patterns, bolt bounce, or excessive wear on your upper receiver extension.