The Standard Infantry Rifle (or SIR) was developed by the United States Government after they lost the Battle of Yonkers, retreated westward, and re-established order. It was used en masse at (and after) the Battle of Hope. This rifle (along with the M16 series rifles) are still being used by the US military after the Zombie War. The SIR also typically fired the incendiary/explosive Cherry PIE rounds.