AR 15 mag catch not seating Pmags

[Bluedragon]

Hello everyone, one of my AR15's is having an issue with magpul made mags not wanting to lock into the mag catch when seated. I can remove the mag by simply pulling on it without engaging the catch, but with standard STANAGS there is no such issue.

I have googled with no solid answer and i have also looked at the parts closely with the rifle apart.. but nothing seems amiss...any help would be appreciated. Thanks

 

[bwframe]

Are you loading the Pmags completely full?

Lotta folks down load Pmags to 28 for easier insertion.

 

[Bluedragon]

Are you loading the Pmags completely full?

Lotta folks down load Pmags to 28 for easier insertion.

The mag i tried was loaded with 25 rounds but it also happens with empty mags. This only occurs with pmags. I haven't tried my thermold and the usgi's are fine. But those i only tested the gun with empties.

 

[MCgrease08]

I have one lower that sometimes has issues with Gen 3 Pmags. No trouble with Gen 2s. The extra ridge on the back of the Gen 3 sometimes hits the bottom of the mag well and prevents it from seating easily.

 

[Bluedragon]

I have one lower that sometimes has issues with Gen 3 Pmags. No trouble with Gen 2s. The extra ridge on the back of the Gen 3 sometimes hits the bottom of the mag well and prevents it from seating easily.

Thank you for posting. I did forget to mention my pmags are gen 2.

 

[Ark]

I have seen bad mag catches before, and I've seen magwells toleranced so loose a magazine can be twisted and pulled out. Either you're not getting positive enough engagement on the mag, or something is blocking the magazine from inserting far enough to engage.

USGI-style mags have a simple hole cut in the side of the mag. PMAGs don't have a hole all the way through, just a little recessed slot. The actual engagement lip is quite narrow. So your catch is probably protruding further into the body of the mag and getting more engagement with the USGI versus the PMAG. The external dimensions of the PMAG are slightly larger than the USGI, as well, and while it's not usually an issue on the AR there are other guns with mag wells that will take STANAG/USGI metal mags but not PMAGs. So try it with the upper taken off and directly inspect how the mag is fitting and how it's engaging the catch.

Consider replacing the mag catch. It's a nothing part.

 

[NyleRN]

Give the mag catch 1 turn in clockwise and see if that makes a difference

 

[Bluedragon]

Thank you gentlemen for the responses, I will do as instructed and look at the lower more closely with the upper removed.

As for turning the mag catch, how does one go about doing that? Thanks

 

[Ark]

Thank you gentlemen for the responses, I will do as instructed and look at the lower more closely with the upper removed.

As for turning the mag catch, how does one go about doing that? Thanks

You can use a pencil or any cylindrical object to push the button far enough that you can spin the catch in one more turn and try that.

 

[Bluedragon]

You can use a pencil or any cylindrical object to push the button far enough that you can spin the catch in one more turn and try that.

Thank you for the video, i will give it a try tomorrow to see if that solves the issue.

 

[Ggreen]

Anderson lower?

 

[Ggreen]

99.999 percent of the time you see this issue is that the lower is out of spec. You can try to correct it with different catches but every in spec lower will accept pmags.

 

[Bluedragon]

Anderson lower?

No, its actually a factory built Core 15. My Frankenstein a2 clone with an anderson lower is fine with all mags including magpul's. Go figure.

 

[Ruger_Ronin]

OP - Is the bolt closed or open when this happens?

 

[Ggreen]

No, its actually a factory built Core 15. My Frankenstein a2 clone with an anderson lower is fine with all mags including magpul's. Go figure.

With core15 you can also be a bit wary. I know it has been an issue on a growing number of Anderson oem'd lowers. Like i said though. I've never seen a fix other than changing the lower completely. Ice heard of guys getting lucky and finding a mag release that stacks with the lower enough to make it work but I've never seen that in person.

 

[Trapper Jim]

I don’t use plastic mags and prefer the precise fit on my Bushmasters for the mag going home with full capacity and no slop. Just me.

 

[Bluedragon]

OP - Is the bolt closed or open when this happens?

So far i have only tried messing with it while the bolt is closed.

 

[NyleRN]

Have you tried putting an extra turn on the mag catch yet?

 

[Ruger_Ronin]

So far i have only tried messing with it while the bolt is closed.

You will likely not experience this with the bolt open,which is more of it's intended operation during reloads. The loaded mag is hitting the bottom of the bolt. After the 30th round is loaded in the mag, you can still push down but not enough for another round. This allowance is for bolt clearance, but is more difficult when done prematurely reloading. Possible solutions:

1.) Download -1 round. Give spring/follower room since it's trying to "bottom out". Top round would be above bottom of bolt face during normal open bolt mag changes.

2.) Insert full loaded mag, tap on bottom of mag to seat fully. Hence the phrase tap, rack, bang. (Do not do the bang part).

 

[Bluedragon]

Have you tried putting an extra turn on the mag catch yet?

Hello again everyone, i have been waiting to reply after having enough time to tinker with it, and its still acting finicky. No idea what is causing it but i will try replacing the mag catch.