King Arms M16 mag stopped fitting in my M4.

[Omi-san]

I own 6 mags. The TM that came with the AEG, 1 CA and 4 King Arms. They all used to fit perfectly in the M4 up to now. For some weird reasons, the King Arms mags don't lock in anymore. Unless I hit the bottom of the mag with the palm of my hand, but even then, the "click" is barely audible.

The TM and CA mags do not have this problem.

The mag release is properly assembled and the hop-up feeder looks normal. The only explaination I can think of is that the plastic body has bent during storage creating tiny 0.015 difference on the mag release position. Is that even possible?

[damage]

Hop up feeding lip is not aligned. That also make the mag feel "tight" when you put one in. I had encountered this little issue from M4's that I worked on.

Edit:
This only applies Metal bodied M4's. One way to tell if the hop up is not aligned is not lined up with the seamline of the gearbox.

To fix this loosen up the delta ring. Put a mag and push the mag release and make sure the mag falls of freely. Then put the mag in and slowly tighten the delta ring then push the mag release again if the mag falls freely.

[Kokanee]

I've had the metal shell of the king arm m4 mags get a little "pinched", if all else fails try using something to pull the metal around the mag catch slot on the mag out a bit.

[Nova316]

Try tighting your mag release screw,
Its on the button u push to release the mag, mine comes loose once in a while

[Omi-san]

The mag release is tight. The problem is that it barely locks on the mag. Once locked, it's hard to release too. I guess the problem comes from the fact that the hole where the mag release is supposed to lock isn't perfectly straight on the KA mag (see pictures).

I don't understand why it suddenly started doing this though. The KA mags were fine before.

I fixed it with a smooth file. The KA mags are working normally now.

[mcguyver]

Take a flat blade screwdriver (big one) and pry up on the area where the wear is on the mag. Insert the screwdriver in the hole (handle of the screwdriver should be at the bottom of the mag) and pry up with a side-to-side twisting motion of the screwdriver. I've had to do it on alot of old mags and some new ones as well, especially King Arms. Works everytime (but usually I end up doing it to someone else's gun on the field with my Kershaw multi-tool).

[Omi-san]

I tried that first, but it didn't work. I really needed to file some metal off and make the top of the slot perfectly horizontal.

[mcguyver]

Bend it out more. You really have to put some muscle into it.

[Regan.S]

Your magazine is probably wore and smaller then it was before. Possibly dented a little bit?

[Savage Haggis]

Temporary Thread Jack Alert

Originally Posted by Regan.S

Your magazine is probably wore and smaller then it was before. Possibly dented a little bit?

...Apologies.

Carry On.