watch out for subgun ammo
Be sure you're not using bulgarian submachinegun ammo. It's purported to be too hot... I had two boxes of it about 5 years ago when I first got my 52, it came on 8 round stripper clips and trigger slapped really bad, empties were thrown yards away and there were fireballs flying out the ejection port, too. I learned later that this stuff was loaded hot for use in PPS and PPSH burp guns, my buddy and I had been told that the x25 round was a zipper, we believed after shooting those two boxes of it.
I've been shooting Romanian surplus in mine lately, haven't noticed the slap being too bad at all... sorry I don't have any smith advice for the pistol, just the fyi safety warning.