"263 project" is a tank fighter developed on the basis of is-7 heavy tank. Since 1950, three design schemes have been carried out at the same time, but only one scheme has completed the full-scale wooden model. Because the production of is-7 heavy tank stopped, project 263 was forced to give up.

From 1950 to 1951, the Kirov factory in Leningrad designed a "263 project" self-propelled anti tank gun. The chassis used a large number of is-7 and T-10 parts. Its combat chamber was rear mounted, and the S-70 130 mm gun designed by the central artillery Design Bureau of graben was used. However, 263 project failed to mass produce and only one model was used for testing.

Control keys 1, 3, 4: hatch

Control key 2: stop plough

Control key 7: light