Got two of them a while back, one locked with no trouble and the other one simply would not enter the receiver of my Zastava pistol. 'PUF Gun' means 'Perfect Unit For Gun'. believe it or not. These mags are 'smoke' translucent with steel lugs but no feed lip liner. I worked on it some then and eventually put them away as I was having remodeling done. Got them out the other day and got really determined to fit the one mag, which turned out to be a 'Jonah' magazine for sure. The problem was it had a bulge in the upper LH side across the body just under the feed lip. I filed on both sides, mostly on the LH side, plus reduced the height of the rear locking lug also by file. I finally got it to lock in but being polymer I left it just a tad tight.
So now comes the loading test, and sure enough, the bad-luck mag would only take 26 rounds. Being translucent, with a light I was able to see the follower was hanging up on the spring rather than slipping over it smoothly, so I pulled the follower and flared the bottom edges toward the inside. Second try also hung up but a tap on the bottom allowed the full load of 30 rounds rather smoothly'. The 'good' one took all 30 without incident, of course.
Bottom line, it was about two hours of work to get that mag basically functional, but I have learned over the years since 1996 how to work on AK mags.

Nice work and thank you for sharing.  I have been tempted to try these and now i am rethinking it. Do you know what generation your are are?