"A S.T.A.R.S. custom automatic. Fires 9mm Parabellum rounds."
If you are playing as Jill, you begin with it in your inventory upon entering the Mansion. If you are playing as Chris, you will find this weapon shortly after discovering the body of your comrade Kenneth; it can be found after returning to the Main Hall after the discovery.
This weapon is good against lesser enemies, such as zombies and crows, but it should be switched out for a shotgun when facing Crimson Heads and other more powerful enemies. It has a small chance to land a critical hit against non-boss enemies, instantly killing them, as well as retrieving used daggers and preventing Crimson Heads if the victim was a regular zombie; this chance is higher when playing as Chris than when playing as Jill.
With proper timing, it is possible to fire this weapon with the same burst-fire as Barry's variant below, the attack button must be pressed at a very specific interval to do this however (2,4 hit per seconds).