I recently purchased an AR15 from a guy and the magazine does not lock correctly. I have to slam the mag pretty hard for it to lock but if I pull on the mag and wiggle it around it will come loose. I have tried two different mag’s (PMAG and a Bushmaster). The lower is a Smith and Wesson but I am unsure of the uppers make… I know its not a S&W though. This is my first AR so any help will be appreciated.

You need to tighten the magazine catch. To do that you need to push the magazine catch as far as you can. The bar will stick out on the left side of the magwell. Turn it clockwise at least one turn. It may be necessary to remove the bolt catch/release but shouldn't with it being as loose as you say.


TS

Thanks for the reply TigerStrip. I've have already tried tightening the bolt catch and that doesn’t seem to be the problem.

Strange.




TS

The spring on the catch could likely be worn out and simply need to be replaced. Also, I would check for wear on the magazine catch. If the edges are rounded or chipped this coulb be the cause of the problem. Either way, there is not much that can go worong with this piece. For what it costs, I would just replace the entire mechanisim. If that still doesn't work, remove the upper and test fit the mag. With the mag in place push the follower past the point where the mag is held in place by the catch. This will give you a better view of how well the mag is being held in place and may lead you to a solution. If you still can't figure it out, your mag well may be warped and I can't really help you there. Going to need to replace the lower to fix that. I can't say that I have ever heard of this happening but there is a first time for everything.

Thanks for the help guys. This gun had not been fired when I purchased it so I wouldn’t think anything would be worn out but I will check these things this weekend.

magazine release is what you need to tighten

to the Armory

If you have tightened the mag catch and it did not work, I would send it back to Smith and Wesson.

S&W had some issues with non-GI mags.

Sanding the mags or inside the magwell helped sometimes.

Try a USGI mag before sending it back. If it locks in and drops right then you know what is going on.

S&W will swap out with you, but if you started with a stripped lower then you might not want to pull it all apart just to ship it back.

I had a crappy PWA HBAR almost 20 years ago - I think it was with Washington at Valley Forge. There weren't a LOT of things on it that didn't need replacing - the mag catch was one of them.

If it doesn't tighten up, then simply replace it. A cheap fix for an AR - there are MORE expensive ones. DEFINITELY go through the bolt carrier group though, and make sure everything there works as well. A worn mag catch could be indicative of OTHER worn parts...

This post has been edited by The War Wagon: November 7th 2009 7:09 PM

Warlike - sorry I ment that I tried tightening the magazine catch.
Nwatson99 - only the lower is S&W so they will work on it.


Well I just removed the upper and inserted the mag and it seems to lock fine. It looks like a have some kind of interference issue between something on the upper and lower. I’m not sure if this has anything to do with the problem I’m having but I do to use a punch on the take down pins to release and insert them. Should things be that tight? I really appreciate the help guys.

Having to use a punch to mate and detach the upper and lower is on the very tight end of spec. The only acceptable reason that a mag doesn't lock with the upper attached is a that a mag is loaded past capacity. Will the mag lock in the magwell with the upper attached and the bolt locked to the rear?



TS

or the magazine feedlips are way out of spec, after trying TS's suggestion, ride the bolt with the mag in, if what we suspect is happening is going on it won't go into battery and will stop at the maglips

Well I figured out the problem. The top rear edge of the mag was hitting on the little lip in the upper receiver below the bolt not allowing the mag to go in far enough to lock. I filled down this lip (a small amount) and things seem to be working now. I probably should have just filled the magazine catch down a little instead but I think it will be okay. I fired 100 rnds threw it on Sunday and the magazine didn’t come loose and I can longer pull the mag loose without releasing the catch. I had a few stove pipe jams and the shells that did eject properly only would go about two feet so I installed a Wolf XP Extractor spring and a D-Finder D-Ring last night. Hopefully this will fix my extraction problems. Thanks for the help again guys.

Let us know how it goes.




TS