US Cartridge, 81mm HE, M56, M56A1
Cartridge M56A1 is a high explosive round intended for use against materiel and personnel, functioning with both fragmentation and blast effect.
The complete round consists of a relatively thin-walled, shallow-cavity steel projectile containing a TNT bursting charge, a point detonating or time fuze, fin assembly M4A1 with propellant increment charge M2A1, ignition cartridge M6 and percussion primer M34: At the time of manufacture, the fuze is assembled and staked to the internally threaded projectile nose and the fin assembly is assembled and staked to the internally threaded projectile base. The hollow perforated fin assembly shaft, which is internally threaded at its base end, receives the ignition cartridge and the threaded percussion primer. The perforations provide for transmission of the ignition cartridge flash to the propellant increment charges. A cellophane-wrapped propellant increment charge is inserted between the blades of each fin and held in position by a spring-clip increment holder. Any or all of the propellant increment charges may be removed for fire adjustment (charge firing) by pulling them from under the increment holder clips.
Primer, Percussion, M34
Collaborative Ordnance Data Repository