New rifle eject issues

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Re: New rifle eject issues

Postby Texas Sheepdawg » Mon Jan 15, 2018 9:36 pm

Rklenke wrote:+1 I've already started the conversation with Ross for a brake... Which reminds me I need to go take a measurement for him.

Also, I tried loads at 30 grains, 31 and 31.5 and still had failure to extract with the lighter loads. I even used some once fired Hornady brass in case it was the brass itself. No luck. I'm now talking to the manufacturer to see if there are any other issues like this. 230 grain FMJs show up tomorrow, so I'll finally have something else to test against.

Just a reminder.
RE, 230 grain FMJs and Lil Gun.
Do NOT use my load data beyond 42.0 grains of Lil Gun. I was WAY out of SAAMI specs on pressures and your rifle will be different than the one I tested those loads with. Start at 38.0 grains and work up slowly. You should start getting a decent seal around 39.8 grains-40.5 grains of Lil Gun and be sure you have a good crimp.
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Re: New rifle eject issues

Postby Rklenke » Mon Jan 15, 2018 9:43 pm

I actually already did your last suggestion, but with duct tape. I marked a line by the rings with pencil to gauge movement. It is creeping slower than before, but still moving.

In other news, Ross brake had been ordered :D
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Re: New rifle eject issues

Postby Rklenke » Mon Jan 15, 2018 9:48 pm

Texas Sheepdawg wrote:
Just a reminder.
RE, 230 grain FMJs and Lil Gun.
Do NOT use my load data beyond 42.0 grains of Lil Gun. I was WAY out of SAAMI specs on pressures and your rifle will be different than the one I tested those loads with. Start at 38.0 grains and work up slowly. You should start getting a decent seal around 39.8 grains-40.5 grains of Lil Gun and be sure you have a good crimp.


No worries, I'm looking for a plinking round that will cycle, not a super death ray. Besides, I enjoy my steel targets WITHOUT holes in them.
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Re: New rifle eject issues

Postby Al in Mi » Thu Jan 18, 2018 5:26 am

your gonna love that brake.

I never had a scope move in a PEPR mount, but like Jim mentioned, make sure you have a even gap between the halves and torque them down.
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Re: New rifle eject issues

Postby plant_one » Thu Jan 18, 2018 2:43 pm

2nd on the fat wrench. lock your scope mount stuff to between 18-20 in/lbs and you're golden.


even without a break on it - that scope should NOT be moving under recoil when properly mounted.


its entirely possible that you have a bad mount - every manufacturer has one get past QC here and there - but start with a hardware check first.

good luck and keep us posted!
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Re: New rifle eject issues

Postby Rklenke » Thu Jan 18, 2018 2:49 pm

My Ross brake should arrive tomorrow, super fast service. Hopefully the scope movement will be a non issue from here on out. I started another thread in the reloading section with 230 grain FMJs for the common man (not trying to replicate 450LM) where I haven't had extraction issues. I'm also at the store picking up some 1680 for the heavies, so hopefully all this is behind us now.
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Re: New rifle eject issues

Postby Rklenke » Sat Jan 20, 2018 3:51 pm

Solved!
For the time being until another problem pops up. I was reading over my emails from GLFA, from which I purchased my bolt and barrel, and noticed in one they mentioned an enhanced extractor. I went and swapped extractors from a retired 7.62x39 bolt, and problem solved.

x39 on left, enhanced 450bm on right
IMG_20180120_164555965~2-716x561.jpg
IMG_20180120_164555965~2-716x561.jpg (115 KiB) Viewed 157 times

The x39 extractor does leave bite marks on the brass, but it works so much better.
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Re: New rifle eject issues

Postby Hoot » Sat Jan 20, 2018 4:59 pm

I've seen and done a few extractor mods to work better with the 450b, but I've never seen one like the one on the right! It seems to be in the vane of accepted mods to work better, but the dimension changes appear much more exaggerated than any I've seen before. You do want the hook moved a little forward and its depth limit opened up a little but geez that looks over the top.

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Re: New rifle eject issues

Postby Rklenke » Sat Jan 20, 2018 5:19 pm

Who sells a 450 extractor that both works and doesn't leave marks on the brass?
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Re: New rifle eject issues

Postby Al in Mi » Sat Jan 20, 2018 5:36 pm

Try Tromix
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