Check all your mags, especially PMAGS, but check all mags!!

[Strongbow]

Inserted by MP:

Siimple explanation and Simple fix of what is the problem is. It took me all of about 10 seconds


What the problem is:
The lip on the un-fixed P-mag pushes the mag release/Bolt catch bar up just enough to catch the bolt group, but not enough to stop it. This will severly damage your bolt group over time. Also if you rest your gun on the mag when you shoot(by the way don't do this) it will shove most mags including FN factory ones.

The Fix:
1.) It is real simple. I used a dremmel and just shaved off about 1/16 of an inch(guessing). SEE PHOTO #1
2.) I took my lower off my SCAR and tested them( You have to push the magazine follower down in order to test).
3.) if the bar lays flat, you have fixed it.(see Picture #4)

HINT:
I also tested all my other "metal" magazines and had to shave a few of them(including my FN mags)




FIXED MAG ON LEFT


FRONT VIEW OF THE RELEASE BAR HITTING THE UNFIXED MAG



WHAT THE UN-FIXED MAG DOES


WHAT THE CORRECTED MAG SHOULD LOOK LIKE(SEE HOW THE BAR LAYS FLAT AND DOESN'T INTERFERE WITH THE BOLT GROUP)














Hey folks,

Over in the "wear and tear" thread we were coming to the preliminary cinclusion that PMAGs are forcing teh bolt catch up and may be forcing the bolt carrier up a bit, causing the bolt locking lugs to suffer some wear with impact to the chamber locking area. I have noticed previously that unmodified PMAGs do not allow the bolt catch to go fully down when the magazine is seated and loaded. I noticed the problem at about 500 rounds and modified all my PMAGs as described below, Since then I have not noticed any additonal wear on the bolt catch. I wasn't aware of potential bolt lug damage before the "wear and tear" thread, so I don't know if the bolt lug peening has ceased, but on mine it is very minor (I can only detect it if I know where t look and shine a light to see the shiny bits), and the gun has had 500 rounds since them. I believe this mod resolved the problem, but we'll see. Hope these pics help those who, like me, just LOVE PMAGs.

This pic shows the OEM magazine seated. Note the proper fully down position of the bolt catch:


This next picture shows an unmodified PMAG seated (I removed the internals for clarity). Note how far the catch is forced up. It's not enough to hold the bolt open, just enough for the bolt carrier to rub along the top of it:


Here's a pic of the wear on the bolt catch caused by this:


Here's the OEM mag (left) compared to the PMAG (right). Note the different rear opening. The bolt catch on the AR platform is directly in the center of the mag, so the shape of the notch doesn't matter on the AR, but on the SCAR, the bolt catch is offset slightly to the left.


Here's the area on the PMAG causing the problem:


The fix is relatively simple. Use a round file to remove a little bit of material from the spot highlighted above so that it looks like this:


A before and after comparison. You don't need to remove a lot of material. Keep the trigger housing (the lower) handy and as you remove material, seat the mag and see if its forcing the bolt catch up. When it no longer does, STOP, you're done.


Lastly, here's the modifed mag seated... no longer forcing the bolt catch up:


Hope that helps!

[SONYtec]

Nice post with photos!!!

[RGriff69]

Great info! Thanks for including the pics!
I have a bunch of Pmags and was worried when I read the "wear and tear" thread.

[mpeltier]

Does anyone know if the Magpul E-mag solves these issues. It is specifically designed for NATO-STANAG spec recievers (Specifically like the SCAR). I was going to order some to test but was hoping to hear from anyone who has tried them.

[joshua79109]

Nice pics, they really show the issue well, thanks.


This is an issue I went though a while back so I thought I'd link another thread where we discussed some of this.

I believe the issues in these threads are all related.

http://fnforum.net/scar16s-and-pmags...ighlight=pmags

[Strongbow]

Does anyone know if the Magpul E-mag solves these issues. It is specifically designed for NATO-STANAG spec recievers (Specifically like the SCAR). I was going to order some to test but was hoping to hear from anyone who has tried them.

We need someone to post a pic of the rear of the magazine to know.

FWIW, the modded PMAGs seem to work just fine.

[Go Navy]

This is about the clearest, most understandable post I've seen so far. Right now I have only one Pmag but have two others on order. I will take a look at all of them.

By the way, you should send your report, with pictures, to the Pmag manufacturer ASAP. In return, they should send you ten modified new mags!

[9unknown]

Wow, great post man. Looks like I'll be spending some time with the dremmel this evening. Hopefully that will resolve the bolt issue until I can get in touch with FN. The wear really is minimal and won't keep me from shooting the scar, I just don't want it becoming a problem later on.

[dzhitshard]

excellent illustration & articulation.
I'm more concerned about overall function than parts wear & was having a little difficulty "seeing" the issue as previously described.

[SgtStrykerUSMC43]

I'm more concerned about overall function than parts wear & was having a little difficulty "seeing" the issue as previously described.

Dude,

The guy has a problem and wanted to share. If you have trouble "seeing" the issue, just ignore the post.

I guess you're having trouble "seeing" that FNF is more than just a forum for super elite, war fighting, target obliterating, ass kicking, laying waste to everything, guys like yourself.

FYI,

FNF has its share of guys who would make you look silly on a range, so a bit of cordial behavior would be in order, eh.