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Mdl1911a1 wrote:PyroDaddy: Went back to check my original order from BCA in prep for a call tomorrow. I've been providing one false piece of info: Gas block is 0.875. I simply mis-remembered. I'll give this info to BCA tomorrow
PyroRobby wrote:Mdl1911a1 wrote:PyroDaddy: Went back to check my original order from BCA in prep for a call tomorrow. I've been providing one false piece of info: Gas block is 0.875. I simply mis-remembered. I'll give this info to BCA tomorrow
Snip:
Note: your barrel diameter at the gas block, if it is like mine from BCA, is .750" or 3/4 inches. The .875 measurement is bigger than the barrel, the bullet diameter is .452, not sure how you are getting .875 as the gas port measurement.
303hunter wrote:I’ve got 18” mid length gas, and 16” carbine gas BCA barrels, and both eject to 4:00-4:30 using A2 buffer systems. Both barrels didn’t work well with the Tromix follower and Lancer mags with front cutout. Lancer mags work wonderfully with 5.56 followers and front cutout. I’ve got 4 Lancer mags with 5.56 followers and front cutout. All 4 are 100 percent reliable. ASC mag with black single feed follower also works well.
I’d try removing a weight from the buffer before I’d drill the port and void my warranty. YMMV
Bmt85 wrote:PyroRobby wrote:Mdl1911a1 wrote:PyroDaddy: Went back to check my original order from BCA in prep for a call tomorrow. I've been providing one false piece of info: Gas block is 0.875. I simply mis-remembered. I'll give this info to BCA tomorrow
Snip:
Note: your barrel diameter at the gas block, if it is like mine from BCA, is .750" or 3/4 inches. The .875 measurement is bigger than the barrel, the bullet diameter is .452, not sure how you are getting .875 as the gas port measurement.
He's saying his gas block journal is .875 in diameter, not gas port. Probably has a heavy barrel profile.
Mdl1911a1 wrote:Looks like I may have confused things a bit.
Buffer and spring must both be at spec weight for the action to cycle. With any additional weight in the buffer, or with an extra power spring and stock buffer, the bolt won't cycle. (more evidence of under-gassed.)
Barrel external diameter at the gas port is .875; this is a heavy profile barrel as BMT85 mentioned.
I emailed BCA today, and they confirm the gas port on my barrel is undersized. The port diameter on a 16" heavy barrel in .450 Bushmaster with carbine-length gas system should be 0.076; or a #43 drill. The existing #50 hole is too small. I've requested an RMA and will ship it back for repair. I was really up in the air about doing it myself, but I have enough other things going on to keep me occupied until BCA can get it done.
Thank you all again for your suggestions and information; it was a great help in zeroing in on the problem!
Al in MI: Thank you for uploading the photos. I'm going to cut a bit of a ramp in the upper's cross piece before I dismount the barrel for shipping.
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