Likely you upped the mass of the shots. Since the mass of the fired projectile(s) is now much higher, the recoil rises to match and your gun literally rips through your actor. There are several ways to fix this.
1. Find a recoil control method (such as the AEmitter method used in the Coalition sniper)
2. Use Lua to apply a force to Actors in range

Both are about equally difficult, though #2 is more daunting for some because it requires knowledge of scripting and most people are more comfortable with ini code.