the way the outer barrel assembly fits into the gun i'm not remotely surprised a slightly loose fit could make the dispersion go crazy, although i got lucky and had one that had decent performance for a regular pistol let alone a cocktail gun i bought as a joke.
Op- this is one of those guns you might not want to run on stronger gases, nuprol green is ok but i found the base seal in the mag really wasnt happy with anything stronger.
On mine I noticed a bit of flash on the hop rubber. I removed it (it just pulls off) and cleaned it up. Now it shoots as well as any WE pistol on a .25 with a very surprising range! I also picked up a threaded barrel from KY Airsoft so you can fit a tracer or small suppressor. It's probably shot more ammo being passed around at the start of games than by me.