AR-15 Help Pmag issue?

Boondock Saint · Oct 19, 2017

You need to use a fair amount of force to get an AR mag to fully seat under a closed bolt. You have to overcome the force that is being captured by the mag spring as it seats on the underside of the carrier. Think about how much force you need to load the last few rounds in your mag. Now imagine pushing it one round further.

Shove the mag in the mag well and slap the bottom to make sure it has fully seated. You don't have to use gorilla strength to get it home, but you don't have to baby it, either.

jrumann59 · Oct 19, 2017

was the bolt open or closed? Take the upper receiver off and slide the offending mag up into the mag well and watch the interaction and see if you can see the issue. Use a good mag that will seat then use a mag that wont and see if you see something out of sorts. Did you build the lower or was it off the shelf, could be problem with mag catch spring. Sorry if this is bunch of things out of order, just spitballing for you.

jrumann59 · Oct 19, 2017

songlaw said:
Good morning.
This crisp morning, I shot a fully loaded 30 round PMAG Gen 2 MOE mag. I released the mag, loaded another, and the mag would not catch. Tried a bunch of others, with the same result.

I read the earlier posts, and shoving with some force appears to have done the trick.

Anyone know if the same issues exist with the Gen 3 PMAGs?

Is it just a matter of being more forceful during insertion of the mag?

Never had an issue with gen 2 or 3 p-mags, lancer mags (actually lancers are little stiffer against a closed bolt), IWI mags, USGI mags. I always try to load mags with the BCG locked back, if the bolt is not locking back on last round you have other issues that may be present.

TexasBob · Oct 19, 2017

A Pmag issue or lower mag well issue ?

Gizmo98 · Oct 19, 2017

clandestine said:
Load the Mags to 28 and it will be easier to seat on a closed bolt.

Since I'm the guy always asking why when told to do something, I thought I'd chime in on this advice. Not loading to full capacity, like many have said, makes it easier to insert the mag with a closed bolt. The reason many choose to load 28 instead of 29 is that the top round will be on the same side (right, I think) as if you'd loaded 30 rounds. One SOP in many military units it to pull the mag out after dropping the bolt to ensure the gun is actually loaded. It's a good alternative to a press check, especially in the dark. It may even be a Marine thing, as everyone I've heard this from has been a Marine.

If you do choose to do a press check, make sure you slam the charging handle home to ensure the bolt is fully seated. :innocent0

davsco · Oct 19, 2017

yes download by one and see if that helps and if not download by two. i've shot plenty of 2 & 3 gun competitions where guys fill their mags chock full and then either cannot get them to lock in, or think they're locked in and, oopsie, the mag drops out. whether handgun or rifle, every mag i may use to reload i fill chock full and then take one out.

jimbobborg · Oct 19, 2017

songlaw said:
Good morning.
This crisp morning, I shot a fully loaded 30 round PMAG Gen 2 MOE mag. I released the mag, loaded another, and the mag would not catch. Tried a bunch of others, with the same result.

I read the earlier posts, and shoving with some force appears to have done the trick.

Anyone know if the same issues exist with the Gen 3 PMAGs?

Is it just a matter of being more forceful during insertion of the mag?

Since most people on here don't read the whole thread :innocent0

Yes, all full magazines require a good pop on the bottom to lock into the magwell. Doesn't matter what generation magazine.

photoracer · Oct 19, 2017

DaemonAssassin said:
The PMAG does not swell when it is fully loaded.

What Magpul calls the "dustcover" on the PMags was not designed to do that. Its actually designed to keep the open end of the mag from deforming if the mag is routinely kept fully loaded. So yes the PMag can balloon out. In fact having shot 3-gun with different mag brands the one thing good or bad about PMags is that they can be jammed in fully loaded on a closed bolt. Only possible because the mag body balloons out some when you do that. Can't be done with stiffer mags like the Lancer Warfighter because of the steel lip extension on the top. You have to run a Lancer at 29 rounds to be able to jam it into a closed bolt because it does not balloon out in the body.

hit3961 · Oct 19, 2017

photoracer said:
Its because the Pmags all plastic case bulges slightly when fully loaded. Which is why if you store your mags loaded you need to put the "dust cover" on the top. That top is really designed to keep the mags from permanently bulging, the dust cover name is just a cover story and a side benefit. On the otherhand the favorite 3-gun mag, the Lancer L5, has metal lips at the top along with a semi transparent plastic body. It does not bulge, however, you will be hard pressed to get one to lock in place if all thirty rounds are in the mag and the bolt is not open, so most load their 2nd mag with 29 if they plan on doing a tactical reload. Lancers are nice because you can always see how many are in the mag as opposed to the Pmags, windows or no windows.

Sports

jrumann59 · Oct 19, 2017

photoracer said:
What Magpul calls the "dustcover" on the PMags was not designed to do that. Its actually designed to keep the open end of the mag from deforming if the mag is routinely kept fully loaded. So yes the PMag can balloon out. In fact having shot 3-gun with different mag brands the one thing good or bad about PMags is that they can be jammed in fully loaded on a closed bolt. Only possible because the mag body balloons out some when you do that. Can't be done with stiffer mags like the Lancer Warfighter because of the steel lip extension on the top. You have to run a Lancer at 29 rounds to be able to jam it into a closed bolt because it does not balloon out in the body.

I disagree. I have not come across a mag that i can't "slap" in fully loaded, yes there are some that require little more than a "slap" but I can get them to lock in. Lancer is one of the harder ones to fully seat fully loaded but it can be done just do not be so "gentle"

songlaw · Oct 22, 2017

Please reread, Jim

jimbobborg said:
Since most people on here don't read the whole thread

Jim:
I read all of the earlier posts, as stated in my post.

I have a LWRC DI, and I have fired about 2,000 rounds through it. This is a new, recent issue.

I did not have this issue previously.
I know that you need to use some force, but you shouldn’t have to use all of your might to seat the mag.

I have been advised to try other mags, as some rifles do not pair well with certain mags. I am going to try that, but am doubtful, because this is after a couple thousand rounds with these mags. I have taken the upper off and observed that the the latch engages when an empty mag is inserted, but when a loaded mag is inserted, it often does not. Will take it to the range and try to replicate.
Thanks for your responses, everyone.

songlaw · Oct 22, 2017

Bolt not locking back after last round.

jrumann59 said:
Never had an issue with gen 2 or 3 p-mags, lancer mags (actually lancers are little stiffer against a closed bolt), IWI mags, USGI mags. I always try to load mags with the BCG locked back, if the bolt is not locking back on last round you have other issues that may be present.

In thinking back, you might have something. The bolt must have not locked back. I will go back and check.

Thanks.

BradMacc82 · Oct 22, 2017

Pmags will swell, especially when they're loaded with .50 Beowulf. They'll swell enough to where you can't physically force the mag home, open or closed bolt - but again, that's when loaded with .50 Beowulf, and they've been sitting fully loaded for some time.

In the caliber it was designed for, I haven't had any issues/drag/sticking when seating the mags - even after being stored to capacity for weeks/months at a time.

songlaw · Oct 22, 2017

Went to the range today, expecting to replicate the problem with the mag not catching. Of course, the issue did not arise today. I did not have to use a lot of force for the full mag to click in place. Go figure.

clandestine · Oct 22, 2017

songlaw said:
Went to the range today, expecting to replicate the problem with the mag not catching. Of course, the issue did not arise today. I did not have to use a lot of force for the full mag to click in place. Go figure.

The Class gave you special powers.

songlaw · Oct 23, 2017

Chad's Class Solves All!

clandestine said:
The Class gave you special powers.

Damn! That AR course must have been even better than I thought it was!
:lol:

AR-15 Help Pmag issue?

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