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| | |-+  Magazines Ejecting Under Recoil
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Author Topic: Magazines Ejecting Under Recoil  (Read 336 times)
ronaldparkerj
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« on: October 02, 2019, 07:36:52 PM »

So since my MDR's second trip back to DT (I think the ejector panel was replaced) it has ran fine for 45 rounds (a 20 round magazine and a 25), until yesterday. I was about 10 rounds in to the 3rd magazine when suddenly the magazine (Magpul 25 round M3) flew out of the rifle.
I though that maybe I had a catastrophic failure (mainly because I have never had a magazine fly out that was properly inserted), but that was not the case. It seemed the magazine just flew out under recoil. I assumed it was my fault as the magazine was inserted on a closed bolt, but then it happened about every 3 rounds after that. Unfortunately, I hadn't brought much ammo (as I was shooting other guns) so I wasn't able to test it again with a different magazine (hoping to do that on my next string of days off.

As mentioned, the magazine in question was a Magpul 25 round windowed M3. After googling the problem I have read that the Magpul 20 round M3s and 25 round M118s are GTG, but not the 25 round M3. I'm looking to get some perspective on this.

1. Have other people had this problem with the MDR or other 308s (out of all the malfunctions with my MDR this is completely new)

2. What is the difference between these magazines that would help alleviate this problem. Wider body? More prominent magazine catch notch?

As mentioned, I haven't made it back out the range to test with my 25 round M118 or 20 round M3s, but I will update as soon as I can. Thanks for any info in advance!
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whiskey91lima
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« Reply #1 on: October 02, 2019, 09:25:19 PM »

I have had the exact same problem with my MDR. It ejected a single 25 rnd Magpul windowed pmag. The weird thing is that it only ejected one of the two that I own. That same mag works in all my other 308 rifles with no problem.

I have since sold the MDR and don't have a remedy for you. But since I found that it was only a problem with one mag, I marked it and didn't use it in the MDR.

I believe the cut for the mag catch is just ever so slightly shallower than other pmags. FYI, the transfer bar for the mag release on the MDR is a poor design that wants to release under recoil. Part of the reason that the mag releases are so stiff is to add tension to prevent releasing on recoil.
« Last Edit: October 02, 2019, 09:28:06 PM by whiskey91lima » Logged
JesseJames38
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« Reply #2 on: October 02, 2019, 09:46:59 PM »

I am not sure what the issue is with your rifle.  Just out of curiosity maybe spit the rifle open and check to see if the counter weight pivot pin walked/fell out.  It would be located right around where the trigger guard is.
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newguy2k3
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« Reply #3 on: October 02, 2019, 09:52:42 PM »

Mine had issues with mags falling out when new. Mostly kac, Larue or older pmags.

First make sure the counterweight is still pinned to the mag release transfer bar up by the trigger. There were quite a few that walked out for some reason.

My particular issue was the mag catch screw itself. It was a sloppy fit in the lower and let the mag catch wiggle enough under recoil to drop mags. I want to say it was a 10-32x2" ss Allen screw that I bought at the hardware store and trimmed to length then ground the head to a slip fitbib the lower. Solved my issues.
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spector762
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« Reply #4 on: October 02, 2019, 09:59:12 PM »

Mine had issues with mags falling out when new. Mostly kac, Larue or older pmags.

First make sure the counterweight is still pinned to the mag release transfer bar up by the trigger. There were quite a few that walked out for some reason.

My particular issue was the mag catch screw itself. It was a sloppy fit in the lower and let the mag catch wiggle enough under recoil to drop mags. I want to say it was a 10-32x2" ss Allen screw that I bought at the hardware store and trimmed to length then ground the head to a slip fitbib the lower. Solved my issues.
that's what I did I used red loctite to keep it in and it's yet to walk out
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ronaldparkerj
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« Reply #5 on: October 07, 2019, 09:44:11 PM »

Thanks for the replies so far. Could someone send a pic of the counterweight so I know I'm looking at the right part? 
I gotta say, there are things about this magazine catch system that seem janky. It seems that the magazine catch does a lot of unnecessary moving.
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newguy2k3
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« Reply #6 on: October 07, 2019, 11:27:15 PM »

I don't have mine handy but it's right behind the trigger I believe. You'll see that the mag release bar moves forward when the front buttons are pressed. The counterweight is pinned to the bar and through the lower to counteract recoil forces on the mag release bar. I believe it was the pin that connects the counterweight to the bar is the one that was walking out
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