Geen Mountain 10.5

[stonerAR]

Hi everyone,
I have a 10.5 GM barrel (5.56) with a .87 gas port size. Is anyone running this barrel I've used an H and H2 buffer with car buffer spring.
300 rounds in and the bcg rides the round from mid-shell and jams it upward , bends it, and leaves bolt lug marks on the brass casing. Do I need H3 buffer and or x-power buffer spring?

Note: I've tried another bcg and different mags
With same results. Brass is ejecting at
1 o'clock area, some fly far some don't

Thank you

[Clint]

The malfunction is most likely the BCG outrunning the magazine

The barrel is very overgassed; 087" is WAAY too big.

No amount of heavier buffer will fix it.

The barrel needs an insertable gas port or adjustable gas block.

[stonerAR]

Green Mountain customer service was very helpful and offered me a full refund.
I think I'll try the ballistics advantage 10.3 Hanson barrel.