Russian Mortar Primary Cartridge

I wish to know which Russian heavy mortar uses this cartridge?
Red paper case with a brass head. Swell above base.
Wad looks like NBL-35. Made by Krasnozavodsk Chemical Factory in 1970.

Rim is 29.4mm. Base is 26.5mm. Loaded length is 126mm.

These are for 120mm mortar projectiles.

Krasnozavodsk made only the case!
The cartridge was loaded by #255 in Nizhniy Lomov.

Thanks EOD. I guessed it may have been for a 120mm but Russia also had a heavier mortar. Now I know who made and loaded it. First one I have found.

The 160mm mortar also used a 26.5mm case but it is like 300mm long. The 240mm mortar is using a screw in cartridge with a massive lathe turned head and separate priming screw.