The A-91 is a bullpup assault rifle developed during the 1990s by KBP Instrument Design Bureau in Tula, Soviet Union as an offspring of the 9A-91 firearm family.

The A-91 is a Russian bullpup assault rifle developed by the KBP Instrument Design Bureau during the 1990s. It is an evolution of the earlier 9A-91 carbine, primarily designed to be compact, reliable, and versatile in urban combat scenarios. The rifle is notable for its integrated 40mm grenade launcher and the use of a bullpup configuration, which positions the magazine behind the trigger, allowing for a more compact design without sacrificing barrel length.

The A-91 uses a gas-operated system with a rotating bolt, similar to the AK-47 and other Kalashnikov designs. However, unlike most Russian rifles, it adopts a bullpup layout, which reduces the overall length while maintaining a full-length barrel, improving handling in confined spaces.

The rifle can be chambered in multiple calibers, including the standard Russian 5.45×39mm and 7.62×39mm rounds, as well as the NATO- standard 5.56×45mm NATO cartridge. Its rate of fire is approximately 600 rounds per minute, with a muzzle velocity of 880 m/s.

One of the most notable features of the A-91 is its integrated under-barrel grenade launcher, designed to fire standard 40mm grenades such as the VOG-25. The launcher has a range of up to 400 meters. The rifle also has a spent-case ejection system that ejects casings forward, preventing interference with the user's face or arms when firing from the left shoulder.

The A-91 was designed by the KBP Instrument Design Bureau as a successor to the 9A-91 carbine, with a focus on creating a weapon suited for both conventional and special operations forces. The bullpup design was chosen for its compact size and ease of handling in close-quarter combat (CQB). Initial production began in the 1990s, and the rifle has since been used in various roles within the Russian military.

There are several variants of the A-91, including different configurations for different calibers and missions:

• A-91M^[1]: The most modern variant, featuring updated materials and improved ergonomic features. Chambered in both 5.45×39mm and 7.62×39mm.

• OTs-14 Groza: A related bullpup rifle also designed by KBP, focused on close-quarters combat and available in 7.62×39mm and 9×39mm.^{[citation needed]}

The A-91 is in limited service with the Russian Armed Forces and various special forces units. Its compact design and versatility make it suitable for urban combat and special operations, although it has not seen widespread adoption compared to more traditional Kalashnikov designs like the AK-74 and its variants.

• 9A-91 carbine
• OTs-14 Groza
• AK-74
• List of assault rifles

^[2]

• World Guns: A-91 – Detailed information about the A-91 at Modern Firearms
• KBP Instrument Design Bureau – Official site of the manufacturer

• 
  The A-91 at Interpolitex 2011.
• 
  The A-91 without a magazine at Interpolitex 2012.

• ADS amphibious rifle

• Firearms Russia
• "A-91M - Modern Firearms". 2018-05-21. Archived from the original on 2018-05-21. Retrieved 2018-05-21.