Looking for an image of a BCG cut-away showing the 3 bore.
Wondering how critical is the bolt tail seal?
Looking for an image of a BCG cut-away showing the 3 bore.
Wondering how critical is the bolt tail seal?
You won't outvote the corruption.
Sic Semper Tyrannis
The fit there is held pretty tight; if we talk about it as a gap all the way around it's held to min. .0004 per side to max .0012. I have seen all of one that, between wear and/or parts that were maybe out of tolerance to start with, it leaked enough gas there to be a stand-alone problem.
This is a crop from an old blueprint for the carrier. You can see the tight tolerances down to +/- .0003 in addition to the true position callouts and surface finish requirements.
Interestingly, the .5315 diameter calls out a .0010 tolerance, but the tolerance block on the drawing doesn't have a value for a four place decimal. Gotta love engineers.
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Honor Necessity
Black River Tactical
BRT OPTIMUM Hammer Forged Chrome Lined Barrels - 11.5", 12.5", 14.5", 16"
BRT EZTUNE Preset Gas Tubes - PISTOL, CAR, MID, RIFLE
BRT Bolt Carrier Groups M4A1, M16 CHROME
BRT Covert Comps 5.56, 6X, 7.62
Stick
Board policy mandates I state that I shoot for BCM. I have also done work for 200 or so manufacturers within the firearm community. I am prior service, a full time LEO, firearm instructor, armorer, TL, martial arts instructor, and all around good guy.
I also shoot and write for various publications. Let me know if you know cool secrets or have toys worthy of an article...
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