AR guys tell me whats going on here.

[battleship]

I just got some new Pmags 556 and loaded them up, popped them in my AR mag well and they wont lock in, unless i take out a few bullets, my AR and sig 556 have BB, the sig will hold the mag if i slam it into the magwell but the AR wont unless its either an empty magazine or it is not fully loaded even when its not fully loaded i have to press it in hard to get it to lock up, this is with the bolt closed, if i lock the bolt back there is no problem, a loaded mag will lock in. So its only when the bolt is closed and i have a a fully loaded magazine that this happens. so what the hell is going on inside that magwell.

[69Mach1]

Who ever made your 10/30 P Mag conversion didn't leave any "buffer" zone for the rounds to move down slightly to compensate for the closed bolt. It's still better than having a P Mag that is "loose" enough to take an 11th round.

[battleship]

These are 10/10 pmags not the 10/30 or 10/20 versions.
I find it very odd that if i take out a few bullets it will hold in the mag well, why does this change things.
It checked the catch out and the BB seems ok but im not an expert eye.

[Joe]

These are 10/10 pmags not the 10/30 or 10/20 versions.
I find it very odd that if i take out a few bullets it will hold in the mag well, why does this change things.
It checked the catch out and the BB seems ok but im not an expert eye.

Where did you get those?

I didn't think 10/10 pmags existed yet. Aren't they set to be released in a couple months?

[battleship]

I got them right here, from a very good seller on calguns. they are brand new, when i first tried them loaded they would not hold at all, though many attempts later they started to hold, just not with a fully loaded mag im think they just need to be broken in.

[Joe]

I got them right here, from a very good seller on calguns. they are brand new, when i first tried them loaded they would not hold at all, though many attempts later they started to hold, just not with a fully loaded mag im think they just need to be broken in.

Who'd you get them from?

I only ask because I still could have sworn they weren't even released yet. I can't find them anywhere online.

[battleship]

PMAG, made by Magpul industries corp.

The PMAG works fine in the sig 556 though i have not fired a round as i just got these tonight.

Yes my other mags ( C Products ) work though i will say i think the BB needs to either be replaced or adjusted as some times they hold and sometimes they need a bit of playing with.

[Coltlover]

Battleship I had the same problem on my AR with my 10/30 P mags.I have a Aero Precision lower and everytime I would hit the range ,Mags loaded and me ready to rock ...Dope ..What the hell,The mag wouldnt lock .I seriously would get mad and push the magazine in and out but nothing,Same thing I would removed 1 or 2 bullets and it would work.After 500 rounds my magazines work flawless! Break them in and they should work.

[Werewolf1021]

Who ever made your 10/30 P Mag conversion didn't leave any "buffer" zone for the rounds to move down slightly to compensate for the closed bolt. It's still better than having a P Mag that is "loose" enough to take an 11th round.

This. Glock 10 round mags do the same thing. The spring will loosen up after use. Put 10 rounds in the mag then leave it to help spring compression.

[mydogsmonkey]

PMAG, made by Magpul industries corp.

The PMAG works fine in the sig 556 though i have not fired a round as i just got these tonight.

Yes my other mags ( C Products ) work though i will say i think the BB needs to either be replaced or adjusted as some times they hold and sometimes they need a bit of playing with.

these PMAGs are probably stubbys that people have made from 20 round kits, they cut them down to size so that it hold 10 rounds

you should know certain magazines won't fit in without lots of force when fully loaded, its just cause theres not enoguh wiggle room in the magazine for the bullets to go down on a closed bolt, try loading it from an open bolt and see if it has the same problem, its just the nature of the beast

[damndave]

They must be stubby PMAGs as the official 10rd PMAG is not yet released.

Most 10/20 and 10/30 PMAGS do not lock in with the bolt closed. There is very little leeway from where you can insert a full mag with the bolt closed and forcing a 11th round in it.

If this is a issue, buy a true 10rd mag and not a modified one.

[sonnyt650]

The AR is designed to lock the bolt back on an empty magazine, and is easiest to load that way. By the 30th round you're definitely fighting the spring for real magazines and the clearance might not be there for California compliant magazines. Rather than risk damaging the magazine's catch hole by forcing it in without clearance, just lock the bolt back.

Another possibility is not enough clearance between the bolt carrier and the magazine itself. Look closely at your bolt carrier: it has grooves cut into it where the feed lips slide through, and the problem is that some magazine feed lips touch these grooves. In my limited experience excess plastic will just wear away through normal use though will have feeding problems in the short term, while aluminum will be bent for clearance and so might exhibit feeding problems thereafter.

In theory stainless steel magazines had better work the first time or they will pretty much always feed poorly. I only have one such ten-round magazine myself which works well so this is just speculation.

[tenpercentfirearms]

The simple answer is that the pressure from the spring pushes up on the bullets. Look at the shape of your bolt carrier group from the bottom (open the upper and lower). You will note that the bullets sit up inside the bolt carrier a bit. When pulling the charging handle, the bullets need to compress to come down some so the bolt carrier can pass. Because the tension is so tight on the converted magazine, it actually prevents the bolt from usually pulling back.

In this case, the bullets are so tight, it keeps you from getting the magazine even inserted. If you down load one bullet it will solve the problem.

The exact same issue exists on my Glock 27. I carry only 8 rounds in my spare magazines so that way if I have to do a hot reload, I reduce the my chance of not seating the magazine properly and have a malfunction.

[battleship]

I have a 10/30 mag i could tell if these are cut down versions they are not, and i can see from how magpul put there logo on the side they are different than the 10/30 mag labeling. As some have said i think they just need braking in, and what tenpercentfirearms said, with 9 bullets in they seat in the magwell.
And yes with the bolt back they seat just fine.

[Untamed1972]

it's not uncommon for any fully loaded mag to not seat on a closed bolt. Have had that happen with GI mags as well.

Took a carbine class a couple of months ago and was using PMags and noticed that even on an open bolt I had smack them pretty hard to make sure they seated completely. I think for future mag purchases I will just go back to using GI mags. They're lighter, seat easier, fit in the mag pouches easier just to name a few reasons.