The A-91 is a Russian bullpup configuration assault rifle developed by KBP. The rifle features an integrated 40 mm grenade launcher, which is mounted under the barrel (though older models had an above barrel grenade launcher). It is similar to the OC-14 Groza assault rifle, another Russian rifle.

The A-91 also features a forward case ejection system like in the FN F2000. It features GP-95 40mm grenade launcher.

The A-91 Spec Ops with GP-95 Grenade Launcher and Pistol Grip

It is only used by William Ye and Field Masters. The player cannot hold the paper weapon due to become unusable that destroys the trigger upon hitting the Gun-wielder.