Gas-port regulating gas-block insert install and DIY manufacture.

[markm]

H2 is the standard for carbine. Carbine gas should be tuned to that.

[constructor]

H2s were made to fix the over-gassed carbine length barrels.

ETA- If you run an H2 and the rifle cycles correctly the port in the barrel is larger than it needs to be. You get more of a recoil impulse and more movement in the rifle than you will if running a smaller(.071-.073) gas port and std buffer.

If you compare it to a SIG spear light that doesn't have a buffer you will see the port in a 16" is .052" where a AR15 with a mid gas system and std buffer can run a .071-.073 port size.
Guys that shoot 3 gun tune their rifles to use very light carriers and smaller gas ports for faster cycle times but also less rifle movement.

[prepare]

If a under gassed gun wont cycle with a H2 would a carbine buffer make any difference?

[joedirt199]

Well I can take several buffers along and start with an H and see what happens.

[ViniVidivici]

H2 is the standard for carbine. Carbine gas should be tuned to that.

Hell yeah, that's what we use in everything, all lengths.

[constructor]

If a under gassed gun wont cycle with a H2 would a carbine buffer make any difference?

Yes, each buffer weight changes ejection angle apx 1 hr. If it doesn't cycle at all something else is wrong.

[markm]

If a under gassed gun wont cycle with a H2 would a carbine buffer make any difference?

Yes. I have a BCM 14.5 middy that is so lean, I have to run an H1 for reliable ejection. It's the exception to the H2 standard.

[prepare]

Confirmed!

Took a 10.3 with a crane spec .070 gas port that would not cycle 223 unsuppressed with a H2 buffer/Sprinco blue, installed an H-buffer and standard spring and now it cycles and locks back.
Sample size of one.

[joedirt199]

Well just tested my BCM ELM midlength 16" and 14.5" with .049 vented set screw gas blocks. Shot all my homemade rounds from 55 gr SP, 55 gr vmax Hornady TAP copy, 75 gr Varget 24 gr load. I didn't even need to open up the vent screw. Locked back my H and H1 buffers with flat wire springs. The 14.5" was sporting a Turbo 3 in direct thread mount. The bolt on that rifle is well broke in and worked like a champ. The bolt in the 16" with old style Turbo K was failing to lock back after a while as it is newer and not as broke in yet. Will have to hand cycle that one for awhile. I was shooting under a metal car port on concrete and the sound would still ring the ears. Accuracy was good and I am always impressed at how well my Hornady TAP copy just stacks bullet on bullet.