The A-91 bullpup assault rifle (also known as A-91M) was developed during the 1990s by KBP (Instrument Design Bureau) in Tula, as an offspring of the A-91 family of compact assault rifles described above in the 9A-91 article. While the A-91 retains the basic gas-operated, rotating bolt action and a trigger unit design from 9A-91, it features a bullpup polymer housing, with an integral 40 mm single-shot grenade launcher mounted under the barrel. The earliest prototypes of the A-91 bullpup were fitted with the grenade launcher above the barrel, and with a front vertical foregrip; current models are fitted with the underbarrel launcher, which also serves as a forearm. The A-91 features a forward ejection system, initially developed in Tula by designers like Afanasiev during the early 1960s. In this system, the ejection port is located above the pistol grip, and points forward.