This is a common issue with AK's. The mag release is a "stamping" and often has "flash" on the edges of the release from the stamping process. These edges are sharp and tend to grab the mag where they contact. I always just take a jewelers file and lightly "break" the edges where they contact the tail on the mags. That should make things a lot smoother.
Youre not taking much off, just taking away/breaking that sharp edge.
I personally think filing the mags is a bad idea, especially if you have more than one gun. By modifying the mags, you may very well be dedicating them to that gun.
You shouldnt have to take off much metal at all with the file, just break the edges and remove the rough/sharp parts. Beyond that, Id say its either the mags or something is up with the mag release.
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