The first rifle you encounter on 13TIRALL.lvl
The Rifle is the third and final projectile weapon to appear in SUPERHOT. It fires 4-round bursts that are unstoppable once fired when tap-firing. It is also capable of full auto fire. When it is low on ammo, it may fire a 1-3 round burst instead. It first appears in 13TIRALL.lvl, and becomes a common sight in your opposition's hands as the game goes on.
Trivia
The Rifle is replaced by the SMG in SUPERHOT VR. The stats are somewhat different, with the SMG lacking the 4 round burst function the Rifle had.