It may have only one machine gun, but it has one hell of a rate of fire.
It's a 12.7 Berezin UB Machine Gun, and it's rate of fire escapes me at the moment. But, it was quite fast.
Other Yak's had more than one. Early Yak-9s had one 12.7 mm MG and one 20mm cannon thru the prop shaft. Pilot complaints prompted the factory to install two 12.7s, plus the 20 mm. The 9T-37 and the 9K, having either a 37 or a 45 mm cannon, respectively, had only one 12.7 mm MG for weight saving/aiming purposes, and because the cannon provided most of the punch.
LJB
