The BMP-1 is a tracked, amphibious, fully enclosed armored personnel carrier armed with a 73mm smoothbore cannon, one 7.62mm coaxial machine gun and the AT-3 SAGGER antitank guided missile (ATGM). The BMP-1 represents a significant improvement over the wheeled BTR series in all aspects, including mobility, firepower, and survivability. Fielded in 1966, the BMP-1 has been modified to serve as a common chassis for a number of additional vehicle types. No longer in production, the BMP-1 has been surpassed by the BMP-2 and 3 in both service in the Russian army as well as export abroad.