It's a big Soviet gun meant for indirect artillery fire, later used as a way to evaporate pillboxes, bunkers, and related concrete structures at point-blank range.

Accuracies/features:
- 1:1 size
- built according to blueprints and actual pieces at museums
- has a 4 minute reload time like it should be in reality (might be changed if no one wants to wait for 240 seconds between each shot)

Historical stuff:
Once upon a time, someone slapped this gun on top of a KV-1 and called it the S-51, it was unpractical as the recoil threw crew off of their seats and damaged the transmission.