The 2S9 Sochor is a lightly armored self-propelled artillery piece used by the OPFOR army. It's based on the T-100 chassis and fires 155mm projectiles. The T-100 chassis interior has to be heavily modified to allow support for the 155mm cannon with auto-loader. The modification paid off and several Asian countries are now in the process of modernizing their heavy artillery division with the 2S9.
While the Sochor is not specifically based on a real-world design, the idea of combining an artillery turret (which is also shared with the M4) with a tank chassis is similar to that of the real-life "2S35 Koalitsiya-SV".
As with the Sochor, the 2S35 utilises a self-propelled artillery gun mounted on a chassis derived from the "T-90" MBT.