How long was the barrel of the largest gun ever used?

Answer:
The Little David 36" mortar was the largest calibre weapon, it stood at 8.53 meters, or 27.98 feet.

The LONGEST barrel for a weapon would have to be the Schwerer Gustav and Dora guns with barrel lengths of 32.48 meters, or 106.56 feet.

First answer by Freikorps. Last edit by Freikorps. Contributor trust: 1 [recommend contributor recommended]. Question popularity: 1 [recommend question].