Cartridge, 106 mm: HEP-T M346A1

filling is 3.5 kg of Composition A-3 (RDX/Wax 91/9). As the projectile impacts with a target the thin steel walls of the shell rupture, allowing the explosive filling to spread in a 'plaster' over the target surface before the delayed action BD fuze functions. The resultant pressure and detonation waves are then transmitted through the target armour to create internal spalling and other destructive effects. The M94B1 perforated steel cartridge case has an M57 percussion primer press fitted into the base and contains a 3.58 kg charge of M26 propellant in a rayon and plastic liner. The flash from the primer also ignites the tracer in the base of the projectile. Maximum range of the HEP-T M346A1 is 6,870 m and muzzle velocity 498 m/s. An inert drill round used to simulate the HEP-T M346A1 is known as the Cartridge, 106 mm: Dummy, M368. It does not contain explosive and cannot be fired. A subcalibre training device used for short-range target practice with the M40 recoilless rifle series was developed as the Rifle, Caliber 0.30, Subcaliber: M9. As this device, which resembled an M94B1-type perforated cartridge case but with a centrally mounted 0.30 machine gun barrel along the centre, fires the obsolete 0.30 rifle cartridge it has largely fallen from use. A more modern device is the Portuguese INDEP subcalibre adaptor which again uses a rifle calibre barrel in a 106 mm recoilless rifle cartridge case, but is chambered to accept a standard NATO 7.62 mm ball or tracer cartridge. It may be taken as an example of several other similar devices. The INDEP adaptor weighs 8.5 kg and is 665 mm long. Giat Industries also produces a subcalibre training round known as the 106 SR NR541 practice system.