I have 4 mags, 2 came with the gun and purchased 2 others. 2 that came with the gun worked fine so did one of the others. The one that had issues seemed as if it was too high and I thought I would need to trim the bottom where the catch is but the one extra was all that I needed and used it only when shooting an alibi. So as not to mix them I marked the plastic with fingernail polish. To limit the muzzle heaviness I copied a friend's aluminum forend. Worked fine! When I received the gun I had lock back issues after firing last round. Some times it would but often it didn't, one mag. more that the other of the originals. If it did lock back the slide would release when mag. was removed, if it didn't it would release when putting another mag. in! Though sometimes it worked as it should. I did have trigger adjustment issues but found a way to correct that. I managed to do quite a few things to make it work for me but everything I did didn't change anything, the gun is as it was received and modifications made can be reversed and the gun returned to as was out of the box.
My issue is: I started having problem with ammo,Was using RWS ben when I purchased more I had jams. Thinking it was ammo I changed to SK. Forgetting my ammo a friend gave me a box of CCI std vel. but I noticed I was getting a few low shots I didn't call. Again thinking it was ammo. But even with SK match and match special in addition to rifle match I had jams. Until after 3 weekly practice 900s still getting those low shots the gun started to jam at the 4 week practice and using the same ammo from the same brick! At the match I used my MatchGun2. During another portion of the match I didn't want to be in I shot the AW for practice. Again I noticed the low shots and also noticed the the low shots occurred when recoil was noticeably lighter! However I could only use 1 mag. the others jammed. Following day I inspected the mags. and found the the front near the chamber was high, allowing the slide to close from the locked back position a round was chambered but if allowed to close slowly by hand it would stop when the rim of the round hit the high spot on the mag. and when removed the rim would hit the high spot and be pulled off the extractor! With a fine file I lowered the high spot and mags work! All of them!! I also removed the heavy small spring in the recoil damping assembly and low/light recoil ended.(at least for now)
My concern is why the mags that seemed to work fine started having problems being too high. I also noticed there is no play. When the mags are inserted they seat firmly without any up/down movement, none at all!! The catch on the bottom of the mag is wedge shaped so that the catch exerts constant upward pressure. I'm wondering if that catch should not be wedge shaped? I have the Russian predecessor and it is not wedge shaped, I also made a copy of the Russian also not wedge shaped, both allow the mag. to move up/down about 1/32". I hate to modify the original if anything I'll make another to try. Is you gun's catch wedge shaped? Do you have any play in up/down movement? I'm trying to determine why things are changing! Because of issues I haven't shot the gun much nor can a figure out why my mags got higher!