https://www.planetminecraft.com/project/1-5-1-scale-2a19-t-12-and-2a29-mt-12-rapira-anti-tank-guns/


2A19 or T-12 is a Soviet-designed 100-mm anti-tank gun. It was the first anti-tank gun to adopt a smoothbore barrel, and to introduce modern armor piercing shot, like the APFSDS. It uses long projectiles that are more powerful than its caliber suggests. The T-12 served as the primary towed anti-tank artillery in the Soviet and Bulgarian armies from the early 1960s to the late 1980s.

MT_12
The 100 mm anti-tank gun T-12, which had entered service in 1961, proved very successful. Its shortcomings had to do with its use of the carriage of the 85 mm anti-tank gun D-48. This was so narrow that the T-12 was prone to topple over its side and could only be towed through the terrain at 15 km/h. Together with some lesser considerations, this led to the development of the T-12A, later known as MT-12, GRAU-index 2A29

taken from wikipedia,