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View Full Version : *UPDATE-PROBLEM SOLVED* Help! My AR mags don't all lock the bolt back.


BLD
04-25-2010, 5:21 PM
I've done a couple of searches, and checked on the web but I can't find the info I'm looking for. I have a mutt build (LRB lower, BCM upper, and DD LPK/everything else) I have 3 C-Products 10 round mags and currently have a Pmag 10/30 that I bought from Riflegear. I sent back the 10/20 Pmag because it's doing the same thing as the 10/30 and one of my C-P mags...failing to lock the bolt back on an empty mag. My other two C-P mags work flawlessly. All three worked great until the third on got knocked off of the bench at the range.

Is it the follower that is supposed to engage the bolt catch? If so is there anything I can do to fix my mags? Also can anyone recommend a good 10 round mag? I'm looking at the AR Stoner line of stainless mags. This rifle is for shooting in 3 gun matches so I really need high quality mags. I don't care about cool 30 round looking mags nearly as much as ones that will function great even after a little abuse.

Thanks.

Noobert
04-25-2010, 5:23 PM
Yes, the follower is supposed to push on the bolt catch

THT
04-25-2010, 5:24 PM
Yes, the bolt catch will be pushed up by the follower. How hard is it to work the bolt catch with you finger? I'm wondering if there isn't too much tension/friction between the lower and the catch.

BLD
04-25-2010, 5:31 PM
The bolt catch feels pretty easy to manipulate and doesn't seem like it has any crud built up in it. Sometimes when I insert a bad mag it will hold the bolt back just fine. Other times it won't hold at all, or it will hold until I move/bump the rifle then the bolt will move foreword partially until the follower stops it.

anniepoks
04-25-2010, 5:34 PM
Yes, the bolt catch will be pushed up by the follower. How hard is it to work the bolt catch with you finger? I'm wondering if there isn't too much tension/friction between the lower and the catch.

try to break your AR open. now cock the hammer and slide to safe.
try pushing the catch back and forth for a good play.
if its sticky, then it should be the catch and not a mag issue.

BLD
04-25-2010, 5:44 PM
Thanks anniepoks. I just tried that and saw the exact problem. The bolt catch works fine. when I put one of the bad mags in the, follower moves foreward in the mag just enough that the bolt catch is able to slip off of the follower. Why are my followers so loose in the mags, and is there any way to fix the issue? Should I just toss them and buy something different?.

Thanks.

anniepoks
04-25-2010, 5:53 PM
Ur welcome! are those mags just bought? - if then call your vendor/dealer.
i have both C-Product and PMag w/ no issues. Dont toss them, if they are willing to send you a replacement or send it back per their instruction, then.
even if they send yo a replacement and said keep those defective ones, cannibalize them for parts. u might need them for repairs. goodluck....

BLD
04-25-2010, 6:51 PM
I got the 10/30 from Riflegear recently. I originally ordered a 10/20 but they exchanged it due to the same issue. I feel bad asking for them to replace it again, but I'm not sure how they sealed it up and don't want to wreck it. The other mag is old and was used when I got it.

Ding126
04-25-2010, 7:06 PM
Throw the Promag away or use it for a door stop

BLD
04-25-2010, 7:18 PM
Throw the Promag away or use it for a door stop

It's a Magpul Pmag. I haven't been brave enough to spend any $$$ on anything made by Promag.

THT
04-25-2010, 7:24 PM
It's a Magpul Pmag. I haven't been brave enough to spend any $$$ on anything made by Promag.

Promags are great for malfunction drills :D

bohoki
04-25-2010, 7:30 PM
maybe you have some aluminum sprue under the spring on the bolt stop and it is causing it extra force

it is 2 springs fighting and one will win aw hope the mag spring will win but sometimes it doesn't but it in my opinion should win at least 98 out of 100 times

so many mag hangups like carbon soot,brass shavings copper shavings

Ding126
04-25-2010, 7:38 PM
Ohh OK Then..don't buy Promag

gemini1
04-25-2010, 7:52 PM
If you cant exchanged your C mags anymore, get a Pmag follower and switch it with your c-mags.

gemini1
04-25-2010, 7:54 PM
Ohh OK Then..don't buy Promag


Dont know about you but, I have 2 10/20 Promags and both's been flawless, I've decided to keep the other Pmags I have

anniepoks
04-25-2010, 8:00 PM
Throw the Promag away or use it for a door stop

try this first before you throw it:

i switched the follower with magpul and it worked fine.
i got a 10/20 round only body where it tends to go a little bit slim on the middle
(so as to accomodate 10 round only) by carving the magpul follower until it smoothly went thru that slim section. i was about to make it a doorstop till this remedy.

BLD
04-25-2010, 8:03 PM
I think I may have found the fix to my problem. I might as well post it here in case anyone else is having the same problem. My bolt catch wont make good contact with the followers on two of my mags. It also seems a little loose. I found this over at ar15.com http://www.ar15.com/forums/topic.html?b=3&f=66&t=479984 This guy was having the same problem and it seems that his receiver was slightly out of spec. A 9mm bolt catch filed down just right seemed to fix his problem. I may have to order one up and see what happens. I'll post my results if I try this.

BTW his pics look just like my problem with different mags.

BLD
05-02-2010, 6:10 PM
So yesterday my Colt 9mm bolt catch arrived. I tried to cut off the excess with some of my household tools. That wasn't working so I headed to Home Depot and picked up a nice Dremel kit that I've been wanting for a while. I got home and modified my new 9mm bolt catch much like the guy over at ar15.com did (link in previous post).

After measuring and removing material several times I got the catch to make contact with the followers of my worst offenders while still having enough clearance for the rounds in my better fitting magazines. I found that the shape of the 9mm bolt catch was causing one of the lugs on my bolt to snag on the catch and prevent it from going all the way back. I then removed some material until the bolt slid effortlessly over the catch every time. I tested several different mags that I have and was happy with the results so I removed the catch once more and used my new Dremel to polish all of the surfaces that I had removed metal from. I also rounded all of the sharp edges that I had created.

Today I took it out and shot 120 rounds through all of my magazines and it worked like a charm. Every magazine (no matter how far the follower is from the back of the mag well) held the bolt open after the last shot. The new bolt catch didn't interfere with the feeding of rounds out of any of my mags either.

It feels good to have fixed the problem myself. I've never worked on any of my guns and I'm glad I tried. I'm one step closer to becoming a gunsmith:eek: (I'm just joking, no disrespect to the real talented smiths out there). I'm moving into the realm of kitchen table tinkerer:43: Now I just need to cold blue the bare parts on my new catch.

If anyone else is having the same problem this may be an easy way to fix it. I didn't take any pictures, but for those wondering, my problem/fix/results were exactly the same as in the link in my previous post.

Sheldon
05-02-2010, 8:38 PM
Nice job!! Always rewarding to do it yourself.

sdfella
05-06-2010, 10:51 AM
Excellent!! This is exactly what i've been needing! Thanks!