The La-7 was originally intended to equip a set of three B-20S 20 mm cannons. However, due to reliability problems with said armament, two 20 mm ShVAK cannons were used instead, the same armament as the previous La-5 series of fighters. A total of 368 fighters equipped with B-20S cannons were produced before switching to the regular La-7. The three B-20 cannons were known as "three pointers" and were liked by test pilots.

It was introduced in Update 1.31. Compared to the regular La-7, the La-7B-20 has worse flight performance and fewer rounds per gun. However, with 3 guns instead of 2, each salvo fired is deadlier with the B-20 cannons. The aircraft has the same Shvetsov M-82FN as the La-7, the decreased flight performance can be attributed to the increased weight of the 3 x B-20 cannons. Try to use boom and zoom tactics, and stay below 4,000 m for dogfights for maximum engine performance.