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Posted: 7/5/2005 10:08:06 AM EDT
| AN empty magazine won't move the bolt catch to hold the bolt open. I think it must be the bolt catch spring is too strong as the bolt catch fits without tight spots and there is plenty of lubrication. Is there any way to lighten the spring in the bolt catch? or does anybody know another reason this problem might occur? Thanks |
I think I need to do this with mine, but what should I look for as abnormal? Basically I've never gotten my BM (I bought it as a new complete rifle) to stay open on any magazine other than the 10 rounder that came with it. If you pull the bolt all the way back, the latch is free and loose, not bound by anything, so I didn't feel that anything was wrong with it, but it just simply doesn't work at all. |
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Just got to look it over good. Split the upper and lower receiver groups, and see how it functions. If it sticks anywhere, take it out and see if you can find any edge that appears a little rough. Shouldn't take much work with a stone. And you'll see a difference. For more clarification, does this only happen when you're shooting - the bolt won't lock back? Or if you put an empty mag in and pull the charging handle all the way back, will it lock back?? If it's the former (when shooting), you probably aren't getting enough gas pressure to push the bolt far enough back. If it's the latter, then keep looking toward the bolt catch. But then, I re-read and see you say it did (or still does?) work with the original 10 rd mag. Not sure how many other mags you tried, but maybe try one with a Wolff spring in it?? Just a thought. Good luck
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It's the former. It always locks back on an empty mag without being shot. Then what should I do to fix the gas pressure problem? Also, could this have something to do with it? I've never taken out the aluminum gas rod and cleaned it. I've probably put a few thousand rounds through it, only had it for about 1 year. Could it be that? |
In my humble opinion, I would suggest you see if you have any recourse with BM (I seem to recall you said it was a BM factory gun). Let them deal with it and make it right if they will. Not sure of their warranties, but I would start there. It sounds to me though that your AR is short cycling. Could be there's not enough gas to push the bolt all the way back. Could be a leak somewhere, or the hole in the gas tube isn't lined up right or partially obstructed. You say it's done this since new? I really don't think I've heard of anyone totally removing the gas tube just to clean it. That would be a chore. If you've cleaned it in the gun and got something lodged in there you could have a problem. But again, if it's done it since new............ Another thought is the buffer spring and tube. Are they right? Have another AR that works with the same buttstock you can swap and see? Does the bolt move inside the upper freely? Might be missing some things to think about, but if you consider what's happening to get that rifle to cycle when you shoot, you can figure out which pieces are involved and check them all out. |
have you checked the carrier key to see if its loose? i have one that did that to me when i first got it... that or check to see if you gas rings are worn. a few of my ar's have around 6-7k through it and i have never cleaned the gas tubes on them and have had zero problems with them. |
What part is the carrier key? But another thing is why does it always stay back on their factory mag? |
the carrier key is the thing at the top with the two screws holding it. what the gas tube mates with when your bolt is closed.  pic borrowed from bushmaster.com did you try with one of my mags back then? maybe its the other mags? |
I've tried every other mag I can get my hands on, and none of them work, even bought 2 new 20 rounders with tough tight springs, and they won't keep it open either. Again, it's strange to me that it will always stay open on their mag (probably a gimmic to get me to buy more of theirs, hehe). I'll check the key when I get home, but I'm almost positive it's not loose, otherwise I'd a felt it every time I clean the bolt. -mark |
Quoc, I shot it the other Day at ASC, after I had maticulously cleaned every bolt part with degreaser, then some soapy water. It was clean and as dry as possible afterwards. I lubed it on the outside of course, shot it, and it ran fine, always sticking back on the empty bushy mag. It stopped 1 out of 3 times on an older 20 round M16 mag (that's what it says on the bottom). Still don't know what's the deal with it, since my friends match target colt always locks back on every mag we give it. What's strange is on some mags that it won't lock back on, you can see it or hear it pause on the mag, then push forward, almost like it catches it for a second, then loses it and slams shut again. any thoughts now? |
sounds like either worn folowers/springs or too stong of a bolt catch spring? |
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