MIL-PRF-71167 Cartridge, 7.62Mm: Short Range Training Ammunition Ball - M973 Cartridge, 7.62Mm: Short Range Training Ammunition Tracer - M974This specification describes the performance requirements and verification methods for the Cartridge, 7.62MM: plastic ball, practice M973, and the Cartridge, 7.62MM: plastic tracer, practice M974. These rounds are commonly referred to as Short Range Training Ammunition \(SRTA\). For the rest of this document both rounds will be referenced as SRTA and each single round by its model number. All requirements in this specification apply to both M973 and M974 rounds, unless otherwise noted that they are specific to the M974 round \(see 6.1\).

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11

MIL-PRF-71167A(AR)

3.5.5 Cyclic rate. The cartridges shall function in the

M60, in the M240B with standard buffer, and in the M240B with

hydraulic buffer machine guns at a minimum cyclic rate of 500,

650 and 500 shots per minute respectively within the temperature

range of -20�C � 1�C to 40�C � 1�C.

3.5.6 Noise level. The noise level of the cartridges at

the gunner's ear position shall not exceed 164 decibels and the

duration shall not exceed 20 ms.

3.5.7 Bullet integrity. The bullet of the cartridge shall

not burst or fragment in the barrel or during its flight.

3.5.8 Target kill. When the target is hit, the projectile

shall mark the target sufficiently to indicate a target hit and

activate a standard target mechanism at a range of 100 meters.

3.5.9 Maximum range. The maximum range of the cartridge

(when fired at standard atmospheric conditions) shall be no

greater than 600 meters. All bullets of cartridges fired at the

maximum range shall impact the ground within a safety fan defined

as 5� to the left and 5� to the right of the line of fire.

3.5.10 Port pressure. The average port pressure of the

cartridges when conditioned for 6 to 12 hours at 21�C � 1�C and

fired at that temperature, shall not be greater than 85 MPa and

shall not be less than 45 MPa.

3.5.11 Match/Time of flight. The trajectory of the

projectile shall match within � 1 mil the service cartridge at a

range out to 100 meters from the muzzle.

3.5.12 Bullet extraction. The force required to separate

the bullet from the cartridge case shall not be less than 20.4kg.

3.5.13 Chemical compatibility. The cartridge shall

maintain its function in the M60 and M240B machine gun after

exposure to commonly encountered chemicals in the field.

3.5.14 Explosive ordnance disposal (EOD). When specified

in the contract or purchase order (see 6.2), the cartridge shall

undergo an EOD disposal test during design verification by EOD

personnel in accordance with EOD procedures prescribed by Army TM

60A-1-1-31.

3.6 Ownership and support requirements. Each cartridge

shall possess the following life-cycle ownership characteristics.

3.6.1 Function and casualty. The cartridge shall function

without casualty when fired at ambient temperature and within the

temperature range from -20�C � 1�C to 40�C � 1�C in the M60 and

M240B machine guns. The cartridge shall not cause any safety