450 Bushmaster Feeding Problems

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Re: 450 Bushmaster Feeding Problems

Postby Siringo » Wed May 05, 2010 8:56 pm

Spinkiller -- how many times have you chambered the factory rounds. The bullet will jump forward a few thousanths each time. Do the rounds still measure 2.23" in overall length. You may be jamming the bullets into the rifling which would make them hard to extract. Just a thought.

With the upper removed from the lower -- can you move the bolt back and forth in its travel easily -- without a cartridge of course. Keep the charging handle locked and you should be able to move the bolt carrier group back and forth -- locking and unlocking.
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Re: 450 Bushmaster Feeding Problems

Postby SpinKiller » Wed May 05, 2010 9:29 pm

Don't think the lower has anything to do with it....

I took a look at the bolt with a magnifying eyepiece to see if I could see any wear. I found a small spot on one side of the lug on the extractor. The wear was not on the lug, but on the body of the extractor. The extractor has a small lug on it and on either side the metal is raised slightly. I took a small file to the side that had the most wear and took it down a bit. I put the rifle back together and manually chambered several rounds. This time they extracted much better. It did stick once...I took a little more of the extractor and took a little off the other side of the lug. (remember it wasn't taken off the lug itself) I hand chambered a few more rounds... better! It is still a bit sticky, but good enough to shoot it again to test.
I believe the extractor added just enough radius to the bolt that it hung up every so often as the bolt attempted to clear the reciever lugs. It chanbers every time without help also.

Time to shoot!
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Re: 450 Bushmaster Feeding Problems

Postby SpinKiller » Wed May 05, 2010 9:43 pm

OH YA, THANK YOU everybody for your input! I wouldn't of thought to look at my bolt so hard if it wasn't for you guys!
I'll try to let you know what happens when I fire it.. hopefully this weekend.
SpinKiller
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Re: 450 Bushmaster Feeding Problems

Postby thebrassnuckles » Wed May 05, 2010 11:11 pm

welcome to the site

;)

good luck.
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Re: 450 Bushmaster Feeding Problems

Postby BD1 » Thu May 06, 2010 8:59 am

Definitely something going on here. Kinda sounds like a sticky bolt cam, but that would cause issues earlier than "half way out".
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Re: 450 Bushmaster Feeding Problems

Postby maxbid » Thu May 06, 2010 9:47 am

SpinKiller wrote:OH YA, THANK YOU everybody for your input! I wouldn't of thought to look at my bolt so hard if it wasn't for you guys!
I'll try to let you know what happens when I fire it.. hopefully this weekend.
SpinKiller



Glad you got it working smoother!
Now go shoot another 30 rounds or so - that's the fun part. :D
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Re: 450 Bushmaster Feeding Problems

Postby hi50 » Fri May 07, 2010 12:39 am

I had that same problem of stuck ammo. I called BM and they gave a shipping label. Weeks later it returned. They never told me the problem. Rezeroed 20 rounds without a hitch. I did notice that if using a previously chambered/ejected round after about 4 cycles, I would get the same problem. I guess bullet jump was taking place.
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Re: 450 Bushmaster Feeding Problems

Postby SpinKiller » Fri May 07, 2010 9:04 am

It would be easier to show you guys, but I'll try again.

Wasn't bullet jump. There was a place on the extractor that was apparently rubbing the chamber lugs on the way through...this caused it to chamber hard on the way in, and on the way out.
It didn't happen without a round, probably because the round caused the extractor to move out just enough to bind up. When shot, it would stove pipe, when ejected by hand it would stick. It did not happen consistantly, not sure why, but when your talking thousands of an inch tolerances, it's anybodys guess. All I know is when I took that "shiny spot" on the extracter down, the rifle cycled better. I still need to shoot it though!
I will take a look at those rounds I chanbered ten times to make sure they didin't gow.
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Re: 450 Bushmaster Feeding Problems

Postby SpinKiller » Sun May 09, 2010 7:52 pm

Shot the 450 Bushy this weekend. It stovepiped every time I pulled the trigger.
Took it home, took the lower off. I chambered an empty round....had to use a cleaning rod to get it out. It was catching in the same place, on the extractor, between the lugs. I took the file to it and this time took it down until the empty round would come out, no problem. Took it back out to test fire. This time it functioned flawlessly, ejecting brass with authority. Awesome!!
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Re: 450 Bushmaster Feeding Problems

Postby wildcatter » Sun May 09, 2010 8:37 pm

SpinKiller wrote:Shot the 450 Bushy this weekend. It stovepiped every time I pulled the trigger.
Took it home, took the lower off. I chambered an empty round....had to use a cleaning rod to get it out. It was catching in the same place, on the extractor, between the lugs. I took the file to it and this time took it down until the empty round would come out, no problem. Took it back out to test fire. This time it functioned flawlessly, ejecting brass with authority. Awesome!!


Sounds like it was an out of spec extractor, poop, things can and do happen. The good news is, you learned all along this trail, you shared it with us and for such we all have been enriched. Good shooting..t
Safety First..t
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