A-91

The A-91 assault rifle is a Russian made bullpup developed by the KBP (Instrument Design Bureau) in the 1990s. It fires the 7.62x39mm or 5.56x45mm NATO bullets, depending on the model. It's magazine holds 30 rounds, and it fires about 700 rounds per minute. It features a 40mm grenade launcher uniquely mounted above the barrel.

Battlefield 3
The A-91 was confirmed by EA in a four page fact sheet. Other than it's inclusion, nothing else is known.