AR15.Com Mobile
PK MI CMMG STAG BLUE FORCE GEAR DPMS VORTEX AIM SKD DEL-TON LARUE
RRA BROWNELLS JT SWFA VERIFORCE DSG MAGPUL FSI GEISSELE RAINIER
» 0 Online
If you use PMAGS with your SCAR, READ THIS!
Strongbow  [Team Member]
I made the following post over at FNForums.net in response to a guy who was having unusual wear on this top bolt lugs. Here's the link for context:


http://www.fnforum.net/pmags-and-the-bolt-catch-t25272.html


Here's the post:

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!

Paid Advertisement
ChickenDaddy  [Team Member]
Good info and clearpics/ directions. Thanks!
Pam202a  [Member]
Thanks for the info.

Did the bolt catch issue cause any type of malfunction in the rifle? What about after the modification?
metroplex  [Member]
May PMag Gen 3 might fix this?
Strongbow  [Team Member]

Originally Posted By Pam202a:
Thanks for the info.

Did the bolt catch issue cause any type of malfunction in the rifle? What about after the modification?

No, I've had no malfunction of any kind either before or after the modification. I only noticed the wear when cleaning one day, and experimented with the mags to find the cause.
Strongbow  [Team Member]

Originally Posted By metroplex:
May PMag Gen 3 might fix this?


Don't know. I gotta think Magpul is aware of this. I'm going to drop them an email in any case.
firedog55  [Team Member]
Strongbow-Thanks for the heads up-Well Done-Thank You
Colt_sporter  [Team Member]
Thanks, I will have to check that out.
RASPUTIN8  [Member]
Huh, I stopped using Pmags in my Scar because it would occasionally miss the next round and fail to feed a cartridge. I wonder if this is why. Gonna file a Pmag down and check.
trex021  [Member]
My reply also in the thread on FNForum

EMags have the same problem on the SCAR.

Here are some pictures of an EMag compared to a PMag and an OEM mag.

EMag on the left, PMag on the right


PMag pushing the bolt catch up


EMag pushing the bolt catch up


OEM Mag functioning properly
DOE  [Member]
Lancer mags do the same. See my mod in the modification section on fnforum.net under Scar forums. Same mod applies to Beta mags.
djpaintles  [Member]
I'm glad I read this thread.

Today we were at the range shooting 2 different SCAR 16's. On my buddy's rifle the P-mag was feeding but the bolt wouldn't close on a full P-mag if the bolt was held open. It functioned if with the bolt closed you inserted a mag and worked the charging handle.

Remembering this thread I pulled out my pocket knife, made 2 quick cuts and had a perfectly functioning mag.

Now I only have about 70 more P-mags to go :) ..........................................DJ
99HMC4  [Member]
Okay, who's gonna make the aftermarket bolt catch that is plastic mag friendly? It's time....
themao  [Team Member]
Moderators, I think this post should be tacked to the top or at least linked somehow permanently.

I wonder why Magpul designed the feedlips the way they did and didn't cut out a similar profile along the back side of the magazine like the standard aluminum USGI ones. I don't own a SCAR and I'm happy with my PMAGs, but this might be important for a certain group of military men using these rifles right now.
js308  [Member]
Thanks for the heads up on that Strong Bow!!!!!!
Stukas87  [Member]
Originally Posted By DOE:
Lancer mags do the same. See my mod in the modification section on fnforum.net under Scar forums. Same mod applies to Beta mags.



I have been running the new Lancer L5 mags about two months now in my SCAR, they dont have any issues the back of the mag is cut just like a (GI metal mag)

Strongbow  [Team Member]

Originally Posted By 99HMC4:
Okay, who's gonna make the aftermarket bolt catch that is plastic mag friendly? It's time....


I'm not sure it can be done... bolt catch on the AR is right in the middle... on the SCAR it's offset to teh side slightly (presumably to shave a little weight). All the mags we have were designed to work with the AR platform, so they didn't have to consider the offset bolt catch. It's VERY easy to modify the plastic mags, and I suspect that future revision will address this issue. That seems the most straight forward fix.

DerekCB  [Team Member]
I find it odd that the emag does this seeing as how it was listed as being produced to work specifically with the SCAR among others. Seems like a very basic thing to check as a manufacturer.
Strongbow  [Team Member]

Originally Posted By themao:
Moderators, I think this post should be tacked to the top or at least linked somehow permanently.

I wonder why Magpul designed the feedlips the way they did and didn't cut out a similar profile along the back side of the magazine like the standard aluminum USGI ones. I don't own a SCAR and I'm happy with my PMAGs, but this might be important for a certain group of military men using these rifles right now.


I think teh reason why is that when they designed the PMAG, they designed it with one rifle in mind: The AR paltfrom. The design is perfectl;y adequate fro teh AR platfrom, and smaller opening means less opportunity for debris to work it's way into the mag. Also, that postion of the back of the mag provides support for the rear of the follower. In the absence of any reason not to do the way they did, I think they thought it was a better design choice. However, the amount material which must be removed is quite small reall, and a trade-off I'm certainly willing to make for my own use. Also, I'd be suprised if Magpul didn't address this in a future revision.
Strongbow  [Team Member]

Originally Posted By Stukas87:
Originally Posted By DOE:
Lancer mags do the same. See my mod in the modification section on fnforum.net under Scar forums. Same mod applies to Beta mags.



I have been running the new Lancer L5 mags about two months now in my SCAR, they dont have any issues the back of the mag is cut just like a (GI metal mag)



Good to hear that Lancer was on top of this. My Lancers were first generation and needed to be modified, but I otherwise like the mags a lot.
101ABN327  [Team Member]
Originally Posted By djpaintles:
I'm glad I read this thread.

Today we were at the range shooting 2 different SCAR 16's. On my buddy's rifle the P-mag was feeding but the bolt wouldn't close on a full P-mag if the bolt was held open. It functioned if with the bolt closed you inserted a mag and worked the charging handle.

Remembering this thread I pulled out my pocket knife, made 2 quick cuts and had a perfectly functioning mag.

Now I only have about 70 more P-mags to go :) ..........................................DJ


Yep! After the mod, we didn't have any issues the rest of the day. I just finished modifying my P-Mags and all are in SPEC now!

Kharma Point to djpaintless for remembering this out on the firing line!!!

101

99HMC4  [Member]
Originally Posted By Strongbow:

Originally Posted By 99HMC4:
Okay, who's gonna make the aftermarket bolt catch that is plastic mag friendly? It's time....


I'm not sure it can be done... bolt catch on the AR is right in the middle... on the SCAR it's offset to teh side slightly (presumably to shave a little weight). All the mags we have were designed to work with the AR platform, so they didn't have to consider the offset bolt catch. It's VERY easy to modify the plastic mags, and I suspect that future revision will address this issue. That seems the most straight forward fix.



We put a monkey into space and I'm using an iPad. It can be done very easily. I know very well the pmags can but modified very easy, I've been doing it for a year on my SCAR, however wouldn't it be nice to NOT have to modify something you buy? Or maybe being able to use the industry standard with out fear of bolt hits? Think about it......
Strongbow  [Team Member]

Originally Posted By 99HMC4:
Originally Posted By Strongbow:

Originally Posted By 99HMC4:
Okay, who's gonna make the aftermarket bolt catch that is plastic mag friendly? It's time....


I'm not sure it can be done... bolt catch on the AR is right in the middle... on the SCAR it's offset to teh side slightly (presumably to shave a little weight). All the mags we have were designed to work with the AR platform, so they didn't have to consider the offset bolt catch. It's VERY easy to modify the plastic mags, and I suspect that future revision will address this issue. That seems the most straight forward fix.



We put a monkey into space and I'm using an iPad. It can be done very easily. I know very well the pmags can but modified very easy, I've been doing it for a year on my SCAR, however wouldn't it be nice to NOT have to modify something you buy? Or maybe being able to use the industry standard with out fear of bolt hits? Think about it......


I should be clear... it can't be done just by building a new bolt catch. It would aslo require modifying the trigger group housing (lower).
Strongbow  [Team Member]
double tap
js308  [Member]
I would rather Magpul just fix the Emag vs trying to make a new Scar bolt catch.
steve100  [Member]
What about the Tangodown mags (they were made to work in the scar)?
Paid Advertisement