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 Sometimes Bolt not Locking Back
parisite  [Member]
1/12/2012 3:13:48 PM EST
On occasion my bolt does not lock back after the last round in the mag. When it does lock back just the least little jarring of the rifle will send the bolt in to battery. It does this with all mags. How can I cure this.
Thanks...........
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Saddlerocker  [Member]
1/12/2012 3:58:30 PM EST
Need more info

Type of rifle, ammo used, gas system length, barrel length, buffer weight, mags used, would be a good start
Circuits  [Team Member]
1/12/2012 4:05:46 PM EST
Originally Posted By parisite:
On occasion my bolt does not lock back after the last round in the mag. When it does lock back just the least little jarring of the rifle will send the bolt in to battery. It does this with all mags. How can I cure this.
Thanks...........


Make sure the bolt catch can move freely - there can be debris both in the channel and the spring/pin hole. If it doesn't move freely, find the cause and fix it. Note - test with the hammer cocked to relieve pressure on the hold-open, and safety on to ensure you don't accidentally drop the hammer without the upper in place, which can crack the BHO or damage the receiver in that area.

Worn mag springs can cause it on occasion - can fix by replacing mag springs or snipping a coil to a coil and a half from the bolt hold open spring. Some builders do that by preference, since the BHO spring really doesn't need to be very powerful to do its job.
parisite  [Member]
1/12/2012 4:06:38 PM EST
I have a new gun with new mags........Thanks.....
Saddlerocker  [Member]
1/12/2012 4:08:22 PM EST
ok, if you want to keep it real simple your gun is messed up.
that sound good?

You need to provide information in order to diagnose problems.
Ptlm724  [Team Member]
1/12/2012 5:39:13 PM EST
A new gun and mags and not just one or two mags that do this? Has the lower been apart from the upper since its been in your possession? If so, was the hammer ever dropped (gun dry fired without the upper receiver on it)? If so, you very likely have a bent bolt stop channel. If that's the case, It can be fixed ONCE or maybe if your lucky twice, but you'll need to take it to someone that knows what their doing to fix it and NEVER do it again. If that's not the case, there are few other things to check.
You might check that the bolt stop spring and spring guide are installed properly in the lower receiver. What kind of lower is this and who built the rifle?
rushmc  [Member]
1/13/2012 3:10:34 AM EST
I have one that did the same. Only mine started out by not locking back at all. I compared how far the bolt catch was moving on the one that did not work, to ones I have that did work. What I found was the catch did not move far enough to catch the bolt. After a bit of invesitgation I found the lower and or the bolt catch release had too much metal between them to allow for full movement of the bolt catch. I removed the catch and release, filed out some of the metal where I could see they were contacting each other (the release and the lower) and put it back together. At this point the catch would work. But then the problem was (similar to yours) when I slammed in a new mag the bolt would release on its own. Taken apart again, a bit more filed out and I no longer have the problem

I know I could have sent the lower back but fixing it myself seemed easier

Just one mans problem to consider

Good luck
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