450Bushmaster.net

I just bought a Bear Creek Arsenal 450 Bushmaster upper receiver(This BCA AR-15 complete .450 Bushmaster rifle length upper has a 16" heavy barrel with a parkerized finish, and features a 1:24 twist rate, with a carbine length gas system. It includes a 15 1/4" MLOK rail, an M4 flat-top forged upper receiver, a BCA bolt carrier group, and a rear charging handle. This .450 Bushmaster upper is compatible with any mil-spec AR-15 lower. This has the new handguard.)Right off the upper had feeding issues and the rear charging handle is difficult to cock/pull back.The magazines I'm using is a Duramag SS .450 7 round stainless steel magazine(with Proprietary Liplack design.)The first two rounds fired no problem,then the third round wouldnt load into the barrel.I tried pulling back the charging handle but it was difficult to pull it back.What's the issue here?

Disassemble and inspect everything. Clean the bolt carrier and make sure the firing pin retention pin is fully seated. Lube everything up and just hand cycle the action to help break it in. If issue continues just keep inspecting each part for abnormal wear. New ARs like to run a bit wet to break in. Don’t be afraid to oil it goood.

Texas Sheepdawg wrote:Disassemble and inspect everything. Clean the bolt carrier and make sure the firing pin retention pin is fully seated. Lube everything up and just hand cycle the action to help break it in. If issue continues just keep inspecting each part for abnormal wear. New ARs like to run a bit wet to break in. Don’t be afraid to oil it goood.

Dripping wet....will help it feed and smooth out any burrs.....after a few rounds clean and oil again.....a AR-15 likes to be wet with oil remember you have aluminum frame rubbing against a steel bolt and spring....aluminum does't like friction its sticky a coat of oil lets everything s l i d e.....

if you';re going to hand cycle for break in - DO IT DRY! zero lube.

like... hose everything down with brake clean. think sandpaper whack-off-gloves level dry.



hand cycle 200-300 times like that and you'll mate all the surfaces with what is essentially a dry-lapping process.


then clean, relube and go back out to shoot.

hth

Any updates on this, ever get it to feed?

The magizines from bear creek work without any jams in my new bear creek upper,my bushmaster upper hangs up alot with bushmaster mags,I was so shocked with the BC upper 30 shots and not one jam,5 round mags are in stock at BC,around 53.00,hope this helps!!!

MasterBlaster45 wrote:The magizines from bear creek work without any jams in my new bear creek upper,my bushmaster upper hangs up alot with bushmaster mags,I was so shocked with the BC upper 30 shots and not one jam,5 round mags are in stock at BC,around 53.00,hope this helps!!!

If you don't mind me asking.
Which upper did you get from BC?

BCA finally sent mine back. After remounting the scope, I took it out to zero it. It seemed to shoot fine. Grouping was within reason at 100yards. I ordered a magazine from BCA , but also ordered a standard 5.56 steel magazine from Brownell's. Which is what I used. It worked fine and gave me zero issues. Only problem is loading the first round, I would have to push the follower down with my finger. Not really a show stopper.