First ar build mag catch issue?

[Garyson1311]

Hey guys so I'm the process of my first ar build and I wanted an opinion. I have an Nfa lw 15 and a cmmg lpk. I am trying to install the mag catch and it takes quite a bit of force to even get it into the recessed spot that its supposed to sit in. It definitely doesn't just sit in it and must be pushed hard and almost pops into place. Once I add the spring, button and tighten it up I can't push the button without a ton of force and when I put that much force on these catch system moves. I am thinking I need to file the spot where the mag catch goes to let it sit there a little more freely without having to wedge it in? What say you? Also I was following cmmgs instructions and they said to put the bolt catch on first, which I did. This definitely made it a little more challenging to get the threads on the mag catch to be flush with the button but I did it. If you guys think that is contributing to my problem for some reason please let me know. Thanks so much!

[ar15barrels]

Don't file anything.
It sounds like it is working normal.

[Garyson1311]

I have to push it stupid hard to get the mag to release and the catch does not reset because once it comes out I have to push it back into place from the side opposite of the button to pop it back into place. It just doesn't seem right.

[VictorFranko]

If it were me, I would relieve (file) the mag catch rather than the lower receiver.
The mag catch is a five dollar disposable part, whereas the lower is neither cheap or disposable.
Trying another mag catch is also a good, cheap option.

[Garyson1311]

That makes sense. I've been watching videos of people installing mag catches and when they do it the mag catch just falls into its little pocket on the receiver with no problems or force. Mine is not like that at all. I believe it is too tight of a fit Because I have to force it in until it pops in just to get it into its spot. I like the idea of maybe filing the catch down a bit to get it into that pocket easier. Maybe I'll try that?

[Jeymz]

Agree on filing the mag catch. 2 of my buddies had to do the same (TM lowers for ares armor). I have the same lower but mine was fine. We also had the same LPKs. I actually took a Dremel to both sides of the mag catch as filing was taking too long. Had to Dremel a little material on both sides.

[Garyson1311]

What do you use to relieve it? Just a metal file?

[Garyson1311]

I see. So just file the top and bottom a bit to make it a little skinnier?

[Jeymz]

It was more towards the top on both sides. Just see where the man catch is rubbing and take off a little material at a time till it moves freely.

[Garyson1311]

What do you mean when you say both sides? Mines getting hung up on the side where you push it through the hole up meet the button (same side as bolt catch) I think that pocket is just too small because it won't just sit freely in there without bring jammed in.


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[VictorFranko]

I am sure he means top and bottom of the mag catch when he refers to "both sides".

[Jeymz]

Sorry I meant the front and rear of the mag catch. Not the "sides".
When I placed the mag catch into the receiver from the top going down into the slot, it got hung up at about 1/8 in before it was fully seated.
I dremeled the rear top side of the mag catch till no rubbing was felt. I then noticed the front of the mag catch was rubbing as well. I had to take a little material off the front as well. Not as much as the rear though. Sorry if this is not clear. I'm at work at the moment. Feel free to pm me your number and we can discuss if you prefer.