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CMI Mags drop bolt

This is a discussion on CMI Mags drop bolt within the The M14 forums, part of the M14 M1A Forum category; I have an SAI National Match M1A that I bought used and have two each CheckMate mags ( 5, 10, and 20 rd). I got ...


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Old May 8th, 2020, 06:36 PM   #1
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CMI Mags drop bolt

I have an SAI National Match M1A that I bought used and have two each CheckMate mags ( 5, 10, and 20 rd). I got some of them in 2007 from 44mag and one recently direct from CMI. They all exhibit the same problem in that the follower does not get a good strong contact to lift the bolt stop and a very small jar or bump will allow the bolt stop to fall off the follower and drop the bolt. Scared the crap out of me the first time that happened.

It looks to me like the followers are a bit narrow at the nose and as the last round leaves the magazine the follower is pushed to the left side of the tube and the front right corner of the follower will start to climb past the right mag lip. When that right corner comes up, the follower pivots on the mag spring and the left rear corner will drop.

I borrowed some USGI mags from a buddy and they will hold the bolt open just fine, so I'm thinking my problem is mag/follower related and not rifle related. I experimented with fixes and found a .030" shim inside the left front side of the tube would keep the follower centered well enough to fix the problem. However, I'm not sure I want to attach shim stock inside my mags.

Anyone else having similar problems? Any good advice and guidance?

CMI 20-rd mag with follower rolled above mag lip.
IMG_2955.JPG


Two CMI 20-rd mags. One on the right has the follower as shown in the first picture. One on the left has the follower under the mag lips.
IMG_2959.JPG

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Old May 8th, 2020, 07:02 PM   #2
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Fairly common issue. Replace the follower with a usgi follower fixes it usually.

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Old May 8th, 2020, 07:23 PM   #3
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hytekrednek,

The guy I borrowed mags from did not want to part with his followers. Imagine that.

Is there any reliable source for GI followers? I would have thought since CMI had a mag contract at one point, their followers would be to spec.

thanks for the reply,

TAB

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Old May 8th, 2020, 07:46 PM   #4
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I got several from SARCO a while back. They were usgi followers and in excellent shape. Price was fair.
The cmi mags work fine as is for most people, but the issue you have is common for the few that have issues with the cmi mags. Maybe just a commercial receiver issue? I have not heard of any issues with cmi mags with real gi m14 rifles. At least it is an easy and cheap fix. Maybe inspect your bolt catch for possible issues before you get new followers just to be safe. Others will probably know more then myself about this issue and what causes it exactly, I just know gi followers fix it usually.

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Old May 8th, 2020, 07:47 PM   #5
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https://www.sarcoinc.com/m14-magazine-follower/

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Old May 8th, 2020, 10:32 PM   #6
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I have the same issue of the bolt not locking open after firing the last round on some 10rd CMI mags. Not a big issue since they are range mags.

Could you post a pic of the shim and where you placed it. Might give that a try. Thanks.

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Old May 9th, 2020, 05:22 AM   #7
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Don't some of the real competition/match shooters adjust/bend/tweak feed lips as needed to prevent undue drag/contact when feeding last round or more?
Could this be the case here, and all it might need is a lip adjustment to straighten follower when empty?

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Old May 9th, 2020, 06:07 AM   #8
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Just so I understand this correctly , you are saying the Bolt will close with an empty Mag in the Rifle after last round fired ?

I would contact CMI about your issue .

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Old May 9th, 2020, 09:57 AM   #9
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I'd suggest that maybe you are having a problem with the rifle and not the magazines...

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Old May 9th, 2020, 10:29 AM   #10
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hytekrednek,

Wouldn't that be a kick if SARCO got their followers from CMI.

osteo317,

I experimented with shim stock to see if that would keep the follower in position, simply taping a small piece in place on the forward upper portion of the left side of the mag wall. No permanent installation yet, but I was thinking JB Weld.

thesurvivalshop,

The bolt will lock back when the last round is fired, 100%. With the empty mag in place, give the rifle a bump or jar and the bolt stop will often release the bolt. One time when the rifle was sitting on a rest and bag with nobody at the bench, the stop released the bolt and it dropped into battery. That's the one that made me jump. That is loud when you are not expecting it. When locked open on an empty mag, it is common for the bolt to drop when I remove the empty mag.

My opinion: The follower simply does not lift the bolt stop sufficiently into position. If I manually lift the bolt stop and lock the bolt back, it is solid, it works as designed. The engagement surface of the bolt stop looks OK to me and the bolt stop works fine with mag followers borrowed from USGI mags.

I do not know if the bolt stop is USGI or SAI - or the characteristics of either to tell them apart. I bought the rifle in a private sale in 2007. I do not know its actual production date.

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Old May 9th, 2020, 10:51 AM   #11
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it could be out of spec issues with your rifle, but I would try the cheap and easy fix first and get some gi followers to try out. check to make sure the lug on the mag has not been filed down any too. Some file down the lug to get them to lock in on tight spec rifles.

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Old May 9th, 2020, 10:54 AM   #12
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take the both magazines apart;; check to see if someone change some parts; check the number of turns in the spring; check to see if the spring is installed the right way !!!!

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