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Posted: 1/28/2011 8:37:11 AM EDT
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! |
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Posted: 1/28/2011 8:55:02 AM EDT
[#1]
Good info and clearpics/ directions. Thanks!
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PA, USA
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Posted: 1/28/2011 9:34:24 AM EDT
[#2]
Thanks for the info.
Did the bolt catch issue cause any type of malfunction in the rifle? What about after the modification? |
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MI, USA
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Posted: 1/28/2011 9:49:04 AM EDT
[#3]
May PMag Gen 3 might fix this?
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Posted: 1/28/2011 9:50:02 AM EDT
[#4]
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. |
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Posted: 1/28/2011 9:52:07 AM EDT
[#5]
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. |
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Posted: 1/28/2011 10:01:34 AM EDT
[#6]
Strongbow-Thanks for the heads up-Well Done-Thank You
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Posted: 1/28/2011 12:39:20 PM EDT
[#7]
Thanks, I will have to check that out.
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GA, USA
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Posted: 1/28/2011 5:48:58 PM EDT
[#8]
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.
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MN, USA
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Posted: 1/29/2011 5:50:07 PM EDT
[#9]
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 http://i36.photobucket.com/albums/e46/trex021/IMG_1533.jpg PMag pushing the bolt catch up http://i36.photobucket.com/albums/e46/trex021/IMG_1534.jpg EMag pushing the bolt catch up http://i36.photobucket.com/albums/e46/trex021/IMG_1535.jpg OEM Mag functioning properly http://i36.photobucket.com/albums/e46/trex021/IMG_1539.jpg |
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GBR
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Posted: 1/29/2011 6:17:37 PM EDT
[#10]
Lancer mags do the same. See my mod in the modification section on fnforum.net under Scar forums. Same mod applies to Beta mags.
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OK, USA
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Posted: 1/29/2011 7:36:11 PM EDT
[#11]
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 |
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NM, USA
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Posted: 1/29/2011 8:58:45 PM EDT
[#12]
Okay, who's gonna make the aftermarket bolt catch that is plastic mag friendly? It's time....
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Posted: 1/29/2011 10:54:46 PM EDT
[#13]
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. |
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USA
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Posted: 1/30/2011 4:23:02 AM EDT
[#14]
Thanks for the heads up on that Strong Bow!!!!!!
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NC, USA
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Posted: 1/30/2011 9:00:19 AM EDT
[#15]
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) |
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Posted: 1/30/2011 10:05:55 AM EDT
[#16]
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. |
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Posted: 1/30/2011 10:50:13 AM EDT
[#17]
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.
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Posted: 1/30/2011 11:34:30 AM EDT
[#18]
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. |
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Posted: 1/30/2011 11:35:43 AM EDT
[Last Edit: Strongbow]
[#19]
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. |
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Posted: 1/30/2011 1:52:22 PM EDT
[#20]
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 |
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NM, USA
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Posted: 1/30/2011 9:52:04 PM EDT
[#21]
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...... 
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Posted: 1/30/2011 10:12:30 PM EDT
[#22]
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). |
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Posted: 1/30/2011 10:58:45 PM EDT
[Last Edit: Strongbow]
[#23]
double tap
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USA
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Posted: 1/31/2011 12:46:59 AM EDT
[#24]
I would rather Magpul just fix the Emag vs trying to make a new Scar bolt catch.
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IL, USA
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Posted: 1/31/2011 1:33:19 AM EDT
[#25]
What about the Tangodown mags (they were made to work in the scar)?
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Posted: 1/31/2011 1:40:18 AM EDT
[#26]
Originally Posted By steve100:
What about the Tangodown mags (they were made to work in the scar)? ARC are square cut on the back |
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ITA
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Posted: 1/31/2011 4:16:00 AM EDT
[#27]
Originally Posted By js308:
I would rather Magpul just fix the Emag vs trying to make a new Scar bolt catch. +1 remember that PMAG/EMAG are not STANAG |
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Posted: 2/1/2011 1:12:33 PM EDT
[#28]
Here's a video to show you the issue and how to fix it.
 |
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Posted: 2/1/2011 1:20:15 PM EDT
[#29]
Originally Posted By FAC: Here's a video to show you the issue and how to fix it.  http://www.youtube.com/watch?v=VIFuVd7-HFsAwesome! Thanks for that! |
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Posted: 2/1/2011 1:27:43 PM EDT
[#30]
Originally Posted By FAC:
Here's a video to show you the issue and how to fix it. http://www.youtube.com/watch?v=VIFuVd7-HFsYou use WOLF ammo 
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Posted: 2/1/2011 1:49:34 PM EDT
[#31]
I do use Wolf ammo, cases of it.
 I can't bring myself to run Wolf out of my 17S, that gets Radway Green when I'm not wanting to shoot small groups and Federal Gold when I do. But the 16S gets the steel stuff, God bless its little heart, and it loves it. |
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Posted: 3/1/2011 10:56:54 PM EDT
[#32]
Originally Posted By Frens:
Originally Posted By js308:
I would rather Magpul just fix the Emag vs trying to make a new Scar bolt catch. +1 remember that PMAG/EMAG are not STANAG Remember, there is technically no STANAG spec for magazines. STANAG 4179 was never adopted. We designed the PMAG for the Colt M16 and the EMAG for non Colt-spec 'USGI compatible' weapons. However, building the EMAG as a 'universal' magazine means it cannot work perfectly with everything. Regardless, in general it seems to run pretty trouble free with military units using the SCAR. |
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Posted: 3/1/2011 11:43:14 PM EDT
[#33]
Originally Posted By Justin-Beard: Originally Posted By Frens: Originally Posted By js308: I would rather Magpul just fix the Emag vs trying to make a new Scar bolt catch. +1 remember that PMAG/EMAG are not STANAG Remember, there is technically no STANAG spec for magazines. STANAG 4179 was never adopted. We designed the PMAG for the Colt M16 and the EMAG for non Colt-spec 'USGI compatible' weapons. However, building the EMAG as a 'universal' magazine means it cannot work perfectly with everything. Regardless, in general it seems to run pretty trouble free with military units using the SCAR. Thanks for popping in Justin. I experienced no failures due to this issue, but I'd rather know the bolt catch is working as intended without rubbing on the bolt carrier (my engineering peeking through here). There is some question if it was causing some bolt lub wear due to raising the bolt carrier some. I dunno. In any case, my PMAGS are all modded now and work 4.0. Any thought of a mod in a future revision? I love my SCAR, and I love me some PMAGs. They seem ideal for each other. :) |
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Posted: 3/3/2011 12:18:04 AM EDT
[#34]
This is a good thread to add to the tacked Gateway thread. Read the first post, then link this thread. I have set a toggle on this thread to keep it out of the archive.
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Posted: 3/3/2011 1:46:39 PM EDT
[#35]
I have no trouble with PMAGS dropping free from mine . Did the mod to the rear of the magazine to clear the Bolt release and she runs beautifully!
cp |
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Posted: 3/22/2011 10:27:35 PM EDT
[#36]
Done.
Literally took aroung 20-secongs per mag. |
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PA, USA
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Posted: 3/30/2011 5:39:29 PM EDT
[#37]
I performed the modification on 4 Emags with a sharp knife. Just slowly scrape away small amounts of material until the desired profile is achieved. If the blade is sharp, the results will be very clean and consistent.
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Posted: 4/9/2013 6:19:50 PM EDT
[#38]
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OH, USA
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Posted: 4/11/2013 11:21:36 PM EDT
[#39]
I found the easiest method for magpuls (before I got rid of mine and went to all GI mags) is to score the area to be removed with a box knife and then break it off with pliers. It does not work with the more brittle Lancer mags.
FYI, even some GI mags drag on the BHO finger and as such I elected to clearance my GI mags the same way. They would drag on the BHO finger when you insert them and potentially cause the BHO to engage after firing one round or just drag on the bolt and wear on it. My advice is to take a few minutes to check every brand of mag you have. |
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WA, USA
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Posted: 8/12/2013 6:14:44 PM EDT
[#40]
I read that the gen 3 Pmags would work with the SCAR, any test this?
Or do they also need modification? |
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USA
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Posted: 8/13/2013 2:05:12 AM EDT
[#41]
I got some of the new polymer HK mags. Anyone know if these are gtg?
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CO, USA
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Posted: 8/13/2013 8:20:35 AM EDT
[#42]
Quote HistoryOriginally Posted By Dokgaebi:
I read that the gen 3 Pmags would work with the SCAR, any test this? Or do they also need modification? Work fine in mine without modification. |
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