Raven .25. At one yard it wouldn't hit anything. The scariest thing about it was the sparks that flew out of the barrel when you fired.
sorry - just saw handgun.......
Springfield EMP 9mm... Bought it used - not new.
The FP would pierce the primers on a few different kinds of ammo - then, upon retreating, would pull a sliver of primer cup with it. That would, in turn, bind up the travel of the FP leading to light strikes on subsequent shots.
Also - it didn't like steel-cased ammo.
-J-