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View Full Version : PMag Problem or Lower Bolt Catch?



FChen17213
08-13-11, 11:24
Long story short, two of my PMags have stopped locking the action open on an empty mag.

"Dump 'em. They're just mags" was my first reaction. After all, GI Mags and other PMags have been still locking the action open. Before shitcanning the mags though....something told me "Not so fast....let's make sure it's not the gun," so I did a few tests.

First I used that same AR (a DDM4V1) and tried over 10 different mags with just those two PMags giving me problems. This would point to those mags. Then, however, I tried those trouble PMags in a Colt 6920....no problems. Then I tried the same mags in a BCM Middy......no problems.

Troubled by this, I stripped down all 3 rifles. I slowly inserted the bad mags in each lower. On both the BCM and Colt, the rear of the follower would catch the bolt catch and push up. On the DD, the rear of the follower would just miss, causing the magazine to bind and not drop free.

Then I examined the lowers and the bolt catches in them. All of the bolt catches would have a little play fwd and aft....I'm assuming that that's normal. However, the DD had a bit more wobble. I suspect that that tiny amount of fwd and aft space allowed the rear of the follower of that PMag to just miss, thus not locking the bolt to the rear.

I don't care about shitcanning 2 PMags. However, what concerns me a bit more is if my rifle needs a new bolt catch or if something's slightly damaged in my lower. A little background on the rifles, the DD has seen a good amount of use....probably about 7000-8000 rounds through it while the Colt and BCM have very low round counts...maybe 1000 or so. I'm surprised most of the PMags are still ticking....they are the Rev Ms but have seen about 10k rounds spread between several guns, and this was after I loaned them to a friend for a deployment to Iraq.

So what should I do? Shitcan the trouble mags and don't worry about it or should I also get the lower checked out?

EW1066
08-13-11, 11:32
Not sure if it is a factor but, have you checked the springs in the two suspect mags?

EDUB

FChen17213
08-13-11, 11:41
Yes, as used as they are, I don't think it's the spring tension. It's just that they have started to "miss" the bolt catch. Yes, those mags have worked flawlessly with that same rifle for thousands of rounds until now.

GTifosi
08-13-11, 11:56
Pull the springs and followers out of those two and swap in springs and followers from a pair that work.

If the issue follows the springs and followers you'll know.
Doing such would also cut any cumulative wear stack up between old mag and old follower by some %-age or another.

Given what you've described, I really can't imagine its the bolt release or it would not be so consistant with just those two mags but an intermittant problem with pretty much anything you jam into it barring mabe a brand new mag.