BCM 11.5 MK2 BFH Upper

[OleBigFoot]

Hey guys, I recently picked up this upper and would like to know what the gas port size is so I can compare future/current builds to. Thanks!

https://bravocompanyusa.com/bcm-mk2-bfh-11-5-carbine-upper-receiver-group-w-mcmr-10-handguard/

[Leonidas24]

According to BCM as of 2017 the gas port diameter is .075". Others have self-measured their barrels and reported anywhere from .073-.076.

[everready73]

According to BCM as of 2017 the gas port diameter is .075". Others have self-measured their barrels and reported anywhere from .073-.076.

.073 was what my buddy measured so .073-.075 as stated above is about right IME

If you wanted to go to .070 or so with a brt insert function should still be fine with most ammo types

[OleBigFoot]

Thanks for the replies fellas, it's running fine suppressed - I just like to know the details of things and can also compare results to others. Would be great to know the exact from BCM, seems like we are somewhere between .073 - .076

[OleBigFoot]

Any other data from anyone?

[ColtSeavers]

Any other data from anyone?

Contact BCM for exact measurement.
Pull the gas block and measure the gas port.
Borescope guesstimate?
Toss an H2 and Sprinco Blue spring in it, shoot it and don't worry about it?

[OleBigFoot]

Contact BCM for exact measurement.
Pull the gas block and measure the gas port.
Borescope guesstimate?
Toss an H2 and Sprinco Blue spring in it, shoot it and don't worry about it?

I emailed BCM, they said pound sand (it's super secret). Not pulling the GB, just not worth it. Again, it's just good info to have for reference for future builds.

[Stickman]

If you want to know the exact diameter of something, the best way to go about it is measuring it yourself. No concerns about mixups, someone else doing it wrong, or anything else.