Strange magazine issue with my AR [Archive] - Glock Talk


View Full Version : Strange magazine issue with my AR

12-20-2011, 12:24
I own an M&P 15 Sport which has performed flawlessly except one issue: I notice that with a closed bolt, sometimes my magazine fails to snap in. Through OCD experimenting methods, I have determined the cause to be the second round in the magazine is tilted up slightly. I can reproduce the problem 100% of the time whether I have 20 rds loaded or 30. Evidently, when the second round is slightly upward, it prevents the top round from dropping down and allowing the mag to snap into the lower. Problem happens with the factory provided Pmag 30 and a DPMS 30 mag I bought when I got the gun. Does anyone else have this issue with AR mags?

12-20-2011, 12:28
Are you slapping the bottom of the magazine after insertion?

12-20-2011, 12:37
Are you slapping the bottom of the magazine after insertion?

I've tried giving it a little whack, but not a full force slam. Was told not to do that because while you're slamming the mag up, the bolt is also being pressured upward. Never understood how you could exert enough force to hurt the bolt, by doing this but I'm new to ARs.

12-20-2011, 12:53
Are you slapping the bottom of the magazine after insertion?

this and ...

are your mags fully loaded? going to be tough on closed bolt with fully loaded mags.

12-20-2011, 12:59
You won't hurt the bolt, jam that magazine in with the meaty part of your palm. Rack a round and fire away! :)

12-20-2011, 15:07
this and ...

are your mags fully loaded? going to be tough on closed bolt with fully loaded mags.

No they're not. I have the problem loading 20rds in a 30rd mag.

Gunnut 45/454
12-20-2011, 17:04
It's a fighting gun -your not going to hurt it -slap the mag home!:upeyes: If slapping the mag home damages the rifle or mag you need a better gun and or mags!:faint:

12-20-2011, 17:43
A photo of the magazine in question (loaded, top down) would be excellent here.

Other than that, a few other details would be nice....

What ammo (or specifically, what bullet weight)?

Double check to make sure the magazine is Pmag and not Promag. Personally, I'd huck the DPMS magazine. Find a third magazine and try that, I find it fairly hard to believe there is a magazine related problem that is affecting both a DPMS magazine and a Pmag (kind of opposite ends of the quality spectrum there). Also, if you can, check them in a properly made AR-15 (Colt, BCM, etc).

Are the magazines clean? Weird crap will find it's way into magazines (even at the range). I think the strangest I've seen was a spent .22LR case, and I wasn't shooting .22LR that day.

Lastly, the loading procedure for an AR-15 is to jam the magazine in (straight in, not rock and lock style), slap the bottom hard, then give it a swift tug down (to make sure it is seated). As Gunnut said, if that damages either the rifle or magazine then something needs to go.

12-20-2011, 21:09
For whatever reasons some of my ARs require using more force when inserting a loaded magazine on a closed bolt.
Won't hurt to try some more, different magazines- you're going to want to have more than 2 mags anyhow.
Colt/NHMTG, D&H, DSG, Okay, Center, Brownells have all worked for me; I have heard of the occasional bad Pmag but I have half a dozen or so with no problems yet.

12-20-2011, 22:06
I had the same issue your describing .I own three pmags and for some odd reason one of them is the culprit .The other two work fine fully loaded to.

Made Man
12-21-2011, 06:56
I HIGHLY doubt it is the gun.

12-21-2011, 21:10
I HIGHLY doubt it is the gun.

I know I'm probably being to careful with it. Ordered another PMAG for it tonight to replace the DPMS mag but my original PMAG does the same thing so I doubt mags are the problem. A post in this thread mentioned that mags are to be inserted straight and not rocked n locked. I had been tilting them in so that is likely the culprit.

12-22-2011, 09:08
put straight in hit the base with some force- in the military it is common to download to 28 rounds in a 30 rounder to give the follower and ammo laod a little space to give when forced against the bolt.