Mags binding PSA rifle

[Mzuri]

I recently bought a Palmetto State Armory AR in 5.56. I have just under a 1000 rounds through it and it has run flawlessly except for one thing. Occasionally a mag will bind so that it is hard to get it to lock in place (this occurs with both loaded and unload mags) and then even if it does lock in, it won't drop free when released. I little tug gets it out. I have spent some time messing with it and have tried pmags of the second and third generations and lancers. They all do it occasionally but the lancers seem more susceptible. I have tried adjusting the mag release in both directions and that does not seem to change things. I have tested all the mags in my M&P 15 and they all work fine there, so it's not the mags or my insertion technique.

I am starting to think it may be the bolt catch because there is never binding when the mags are inserted with the bolt locked back. It's not that the bolt is interfering directly, because mags will stick even with upper removed. But as much as I look at it I can't see how the bolt catch could be interfering with the mags.

And this binding only happens 1 out 5 times with lancers ands 1 out 10 with pmags. The rest of the time the mags lock in easily and drop out as they should.

I am baffled.

Any thoughts?

 

[mckenney99]

It really sounds like the mag catch may be screwed in 1 turn too far. Perhaps a catch that is slightly too tall or wide, in which case trying another mag catch might solve the issue. Can't be to complicated as long as there is clearance all the way around the magwell (need to remove the upper to look), not much there to interfere.

 

[Ivan the Butcher]

Have you eliminated the possibility of a bad mag? The next time any mag sticks place a mark or piece of tape on it. Try that mag several times. This is to be sure the feed lips and mag catch notch line up or not.

This is the same remedy for the same problem in 1911's.

Now you are sure which area to pursue.

Ivan

 

[Mzuri]

Because the problem occurs with every type of mag I have tried I don't think it can be attributed to a particular mag or type of mag. I have also tried the mags in another rifle and they all work fine in it.

 

[mckenney99]

"I am starting to think it may be the bolt catch because there is never binding when the mags are inserted with the bolt locked back. It's not that the bolt is interfering directly, because mags will stick even with upper removed. But as much as I look at it I can't see how the bolt catch could be interfering with the mags."

The only part of the bolt catch that should be touching anything is the little extension that contacts the follower only.
However, in playing with one of my AR lowers with the upper removed I did see that if the little extension on the bolt catch that is supposed to contact the top of the follower is a little short, it could actually be missing the top of the follower and slipping to the rear of the follower and dragging on the magazine. Remove your upper and then repeatedly insert your different mags and check to see if your bolt catch can move to the rear of the follower. The extension on the bolt catch should engage the follower by around 2/32 - 3/32nds.

 

[wetdog1911]

How difficult/expensive is it to replace that little extension that contacts the follower? Zero experience with any ARs, but had similar problems with a 1911.

Bought a used .45acp top end for my SM ACE that the guy I bought it from had over polished doing a DIY refinish.

He had also over polished the part of the slide stop that contacted the follower and I would get intermittent failure of the slide not locking back. The ACE uses a different slide stop, stamped with a #2.

Anyway, replacing the S.S. cured the whole issue, but the amount he removed was so slight, you couldn't tell just by eyeballing. So, just slightly short can make a world of difference. A brand new blue S.S. was a whopping $15.

Hope yours is a likewise easy and cheap fix.

Rob

 

[mckenney99]

Both parts could probably be found for around $20 - $25. With proper tools, 1 proper punch, and the knowledge, both parts could be replaced in about 10 minutes.