Cartridge, 90 mm: HEAT-T M431, M431A1 and M431A2
Armament
M36 Cannon on M47 series MBTs; M41 Cannon on M48 series MBTs up to (and including) M48A3.
Development
The 90 mm HEAT-T M431 series was developed during the late 1960s and replaced the earlier M348 series, although stocks of the latter may still exist. Although no longer in service with the US armed forces, the 90 mm HEAT-T M431 series is still used by many other armed forces and remains in production with some nations (see below).
Description
The 90 mm HEAT-T M431 series are all fixed rounds with the projectiles crimped into their brass cartridge cases. A plastic obturator band (normally protected by a grommet until loading) encircles the projectile just forward of the case/projectile junction.
The projectile consists of a steel body, a threaded standoff spike assembly, an aluminium chamber and a fin and boom assembly. The aluminium chamber adapts the fin and boom assembly to the body and contains the base detonating fuze. The projectile nose cap contains a piezoelectric element. An M13 tracer is threaded into the base of the boom assembly.
As the round is fired the propellent gases propel the fin-stabilised projectile from the body and ignite the tracer to burn for at least the first 2,280 m of the trajectory. On impact the piezoelectric fuze functions to ignite the shaped charge formed from 544 g of Composition B under a funnel-shaped liner. The resultant high-temperature metal particle jet can penetrate approximately 190 mm of steel up to an effective range of 1,000 m.
The rimmed cartridge case used for the M431 series is the M114A1 (M114E1) which uses an M79 percussion primer press fitted into the base. The case filling is 3.74 kg of M30 propellant.
The main differences between the M431 series rounds involve the cartridge case wear-reducing liners. The M431 does not have a cartridge liner. The M431A1 has a wax impregnated titanium dioxide liner intended to reduce barrel wear. The M431A2 also contains a titanium dioxide liner with a high melting temperature wax and a mylar barrier.
The 90 mm HEAT-T M431 projectiles have a muzzle velocity of 1,204 m/s and while the maximum range is 8,138 m the maximum effective range is limited to 1,000 m.
Specifications
Weights:
complete round - 14.97 kg
explosive - 544 g Comp B
propellant - 3.74 kg M30
Lengths:
complete round - 914.7 mm
cartridge case - 615 mm
Muzzle velocity: 1,204 m/s
Max range: 8,138 m
Max effective range: 1,000 m
Authorised fuzes
BD M509A1
Equivalent rounds
ITALY
Manufacturer
Simmel Difesa SpA
Type: HEAT-T M431
Description: Standard US specifications
KOREA, SOUTH
Manufacturer
Korea Explosives Company Ltd
Type: HEAT-T M431A2
Description: Standard US specifications
Manufacturer
Poongsan Corporation
Type: HEAT-T M431A2
Description: Standard US specifications but uses brass KM197 cartridge case
SPAIN
Manufacturer
Barreiros Hermanos Internacional SA
Type: HEAT-T M431
Description: Standard US specifications
Manufacturer
SANTA BARBARA SA
Type: HEAT-T ME-431
Description: Understood to be standard US specifications
TURKEY
Manufacturer
Makina ve Kimya Endstrisi Kurumu (MKEK)
Type: HEAT-T M431
Description: Standard US specifications. Production as required