did you just count the shots or also the impacts?
im asking because at some point i noticed, that you can shoot as long as your client thinks there is enough ammo in the gun, but as long as the server says there is no ammo/clip in that gun, no shots are actually fired and can hurt people
had this with a clip in my ak (as 2nd weapon in my hands), and stuff not updating as long as you don't put them on the ground

either way this is something that should be addressed at some point, but if it only fires those shots locally, it should have a lower priority imo

I noted that I didn't think to count the impacts. If I find another handgun and magazine I'll try it again, but it's hard to do by yourself through the muzzle flash.

Server/client lag makes sense to me. A max shot counter should be simple enough to implement client-side as a fix.