PP-19

The PP-19 "Bizon" is a 9mm submachine gun developed in the early 1990s at Izhmash. It is used by the MEC in Battlefield 2. And is featured in Battlefield 3 : Back to Karkand.

Battlefield 2
In Battlefield 2, the PP-19 is issued to the MEC Anti-Tank Kit. It is very similar to the MP5, with the exception of the addition 15 rounds to each magazine. This gives the PP-19 a slight advantage over the other submachine guns.

Battlefield 3: Back to Karkand
The PP-19 has been confirmed for the Back to Karkand expansion, seen here: http://bf3blog.com/2011/10/battlefield-3-back-to-karkand-weapons/ along with 9 other weapons.