
HEAT-T cartridge M66 is a chemical energy armor defeat cartridge.
This cartridge is fixed, with cartridge case M5A1 crimped to the projectile. The cartridge case is loaded with loose M2 propellant and fitted with percussion primer M23A2. The projectile, of multipiece steel construction, contains a copper cone and shaped charge of Composition B, and a base detonating fuze that may or may not contain a tracer.
Composition B shaped charge. Could also be 50/50 Pentolite (0.75 lb, 0.34 kg)
Propelling charge - M2 propellant (0.4 lb, 0.18 kg) or FNH powder (1.04 lb, 0.47 kg)
TM 9-1300-203, Artillery Ammunition (1967)
TM 9-1904, Ammunition Inspection Guide (1944)