.450 build not cycling

Talk about the AR15 style rifles chambered in 450 Bushmaster.

Moderator: MudBug

Re: .450 build not cycling

Postby Hoot » Fri Sep 21, 2018 5:31 pm

1: Different block though I doubt it will solve the problem. More of a "General Principle" thing.
2: Drill it out in increment.
3: Enjoy shooting for shooting's sake


P.S. Get a steel gas block. The melonited (black nitrided) SS ones are easier to clean.
In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: .450 build not cycling

Postby plant_one » Fri Sep 21, 2018 10:33 pm

joegun53 wrote:I think I will try a different gas block. there's 4-5 thou. slop in the barrel (.748 barrel vs. .753 gas block) and 3 thou. on the tube vs. hole in block. Probably too much.

ok so your journal is 0.002 undersized and your block is 0.003 over... bad combo....

go to the gun store, take your calipers and find a block that ID's at .749 tops. 1-2 thou is ALL you need to get one to seat right and seal. shouldn't be hard to do. if you dont have a LGS - call BCA back and ask them to find you one at .748 or .749 so that it matches your gas block journal properly.

you should have to turn a block to seat it... if it slides on like stepping into a hoolahoop you're gonna have problems - every time. 0.005 varience might as well be a hoola-hoop. caliber be damned at that point. even a 5.56 with a hugely oversized gas port wouldnt run right with that poor of a fit.

do NOT put a drill bit to the gas port until you have a properly sized block installed.
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