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Posted: 4/4/2010 3:51:52 PM EDT
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I am having an issue with some of my PMAGs. Out of 22, 9 have failed to engage the bolt catch after the last round. I suspect that this is an issue with the plastic on the follower and could probably be fixed with some trimming.
Has anyone else experianced this? Any fixes? |
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Quoted: I am having an issue with some of my PMAGs. Out of 22, 9 have failed to engage the bolt catch after the last round. I suspect that this is an issue with the plastic on the follower and could probably be fixed with some trimming. Has anyone else experianced this? Any fixes? I had a similar problem. The solution was to buy +10% mag springs. http://www.ar15.com/forums/topic.html?b=3&f=17&t=489740 http://www.ar15.com/forums/topic.html?b=3&f=17&t=489740 |
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13 of the 22 PMAGs do work. I notice that there is a plastic stopper on the inside of the mag body that prevents the follower from riding higher after the last shot. I filed the stopper down and now the follower rides all the way up just like a GI mag. I suspect that this will solve the problem, but will have to test fire to be sure.
All PMAGs will engage the bolt catch when it is cycled dry. The problem occurs during live fire. I will also try the 10% increased springs if trimming does not work. |
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Quoted:
13 of the 22 PMAGs do work. I notice that there is a plastic stopper on the inside of the mag body that prevents the follower from riding higher after the last shot. I filed the stopper down and now the follower rides all the way up just like a GI mag. I suspect that this will solve the problem, but will have to test fire to be sure. All PMAGs will engage the bolt catch when it is cycled dry. The problem occurs during live fire. I will also try the 10% increased springs if trimming does not work. Sounds like you have the latest 'm-rev' 30-rd PMAGs? The follower is designed to NOT come all the way up to the feedlips but this will not affect bolt-catch function. If the catch will engage when dry firing then it sounds like the gun could be short-stroking when firing. That or you may have a short bolt-catch. While anything is possible I do not see how a stronger spring will help unless you're running full-auto at a very high cyclic rate. Follower travel is much smoother in a PMAG than in a USGI mag so there should be minimal friction. The spring used in a PMAG is a standard USGI stainless spring at the same rate. We're you able to try the mags in a different weapon? What make gun are you running? |
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Quoted: I am running them in a LWRC M6A3. I have not tried to use them in any other weapon. The nest way to tell what is happening is too use a PMag and a USGI mag while the upper and lower are separated. Insert the USGI mag and see if the power of the spring will push the catch up. Then try the same with the PMag. My PMags would not "always" push the catch up hard enough to then hold the bolt open. The stronger springs solved that problem. |
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Are PMAG springs the same design as the 10% increased power springs? Can they be easily interchanged?
I did file down the plastic stopper on one of the PMAGs. I noticed that the follower is much smoother for the last three rounds. This alone might solve the problem, but I will have to test fire to be for sure. I am certain that the issue is not the weapon because I have not had a single misfeed with these PMAGs and have fired over 400 rds and 13 of the 22 mags do hold the bolt to the rear after the last shot. I first noticed the problem when the last round of a PMAG was not chambered. The follower did not push the round up fast enough for the bolt. Another time the bolt catch did not engage after the last shot. After these two failures, I loaded up all 22 mags with only 3 rounds and shot them at the range. 9 out of the 22 failed to engage the bolt catch after the last shot, but all cycled. I then examined the PMAGs closely and noticed that the mag followers are smooth until the last few rounds because the plastic stopper creates some friction. I suspect that this friction is the cause of the failures. Extra power springs could mitigate this. I am not bashing PMAGs and still believe that these are one of the best mags on the market. I believe that there has to be a simple fix and suspected that others probably had the same issue and wondered how they fixed it. I know that one fix could be 10% extra power springs. I did remove the stopper from one and noticed that there is no more friction and the last three rounds will dry cycle fine. The follower does stick up in the from an puts pressure on the lips, but the dust cover eliminates this stress for storage. I will have to live fire this mag to be for sure. I also suspect that the mags that have failed will fix themselves the more they are used, If the friction is the cause. |
| have u tried regular USGI mags? Or just P-Mags? Is it possible yer bolt catch is sticking? Try playing with it and see if it moves freely and should have just the slightest amount of play fore and aft. Also if the mags are holding the bolt open when just manually operating the weapon, try different ammo, could be a short stroke. What ammo are ya running? |
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My focuss at this point is on the PMAGs. 13 of them worked perfectly. 9 did not. I wonder if the 9 that did not simply just need to be broken in. Someone on the LWRC forum mentioned using a wooden dowl and moving the follower up and down about 40 time to losen it up. This seems plausible and would also explain why a 10% extra power spring fixed a similar issue.
Any thoughts? |
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I think I know what is going on as well as the fix, but I will have to live fire to be for sure.
I think that the forward inertia of the follower generated by the recoil is causing the friction of the stopper to slow down the follower and thus allowing the bolt to shut before the bolt catch is engaged. I dremeled out the material in the front of the follower where it has been sticking at the stopper. My mags no longer stick at the top when I push down with my index fingure on the front of the follower. I suspect that these mags will now engage the bolt catch after the last shot, but I need to live fire to be for sure. I will post pictures and illistrations if my test prooves my hypothesis. |
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I tested my hypothesis through live fire and concluded.
1. PMAGs and LWRC M6A3 are not defective. 2. There is no design defects in the followers of the PMAGs. 3. None of the PMAGs that I purchased were defective. 4. The issue was the result of a combination of the PMAGs and an aftermarket extended bolt release made by Phase 5. The added weight of the Phase 5 combined with the delay of the wedge of the m-rev follower caused the failure. The PMAGs would likely have engaged a Mil-Spec follower and a Phase 5 would likely work well with a standard GI mag. The combination of the two perfectly functioning devices caused the failures. 5. Removing the wedge feature of the follower did not work an infact made even the workable mags non-functioning. The wedge allows the follower to strike the bolt catch without the need to ride high enough to contact the lips. 6. Solution: - Replace the Phase 5 with a Mil-Spec bolt hold open device. (Note: The MAGPUL B.A.D. is lighter an will likey work, but the reciever on a LWRC M6A3 is to thick and the BAD will partially engage the bolt catch causing it to engage prematurely. The Phase 5 was a workable alternative for the LWRC). - Remove the stopper or modify the followers in the PMAGs to allow the follower to contact the lips. This solution allowed the PMAGs to function with the Phase 5 bolt release 100% of the time. The draw back is the follower contacts the lips, but maximum use of the dust cover should mitigate the added strain. 7. I don't recommend that MAGPUL change anything on the PMAG due to the fact that this issue was caused by customized non-Mil-Spec parts. I also don't want to exchange Pmags. I would simply be exchanging good mags for good mags with no change to the situation. I will likely file down the stoppers on my PMAGs and continue to use them with my Phase 5 bolt release and keeping the dust covers on the PMAGs when not in use. I like both products and don't want to give them up. I am also confident that these PMAGs will work. I fired over 500 rds out of them with no failures except for this issue and now I know how to fix it. These PMAGs also seem better than other mags. I was impressed with how easy it was to exchange followers and mag bodies at the range while conducting these test. I especially like being able to keep them loaded. |
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