Royal Ordnance L9 is a British short-barrelled 165 mm calibre gun used for combat engineering, particularly the demolition of defences. The gun is capable of firing a High Explosive Squash Head (HESH) demolition projectile distances up to . The HESH shell contains 40 lb of C-4 explosive. The L9 gun was mounted on Royal Engineers AVRE versions of the Churchill tank post-Second World War, and on the Centurion tank. The gun's primary purpose is for clearing obstacles such as walls, fences, roadblocks, bunkers, etc. or for destroying buildings.