Shell casing 105 x 617 mm DM 3 / DM 40 (Inert)
The 105×617mm (4.1 inch), also known as 105×617mmR, is a common, NATO-standard, tank gun cartridge used in 105 mm guns such as those derived from the Royal Ordnance L7.
The 105×617mmR cartridge was originally developed from the 84 mm (3.3 in) calibre Ordnance QF 20-pounder 84 × 618R cartridge as part of the development of the L7 105 mm rifled gun.