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 \(see 6.1\).

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MIL-PRF-71167A(AR)

3.7.1 Waterproofness. The cartridges after submersion in

21�C � 1�C water for 2 hours shall maintain its functional

reliability in the M60 and M240B machine gun. The mean velocity

obtained shall not vary by more than � 30 m/s from the velocity

at 21�C � 1�C (see 3.6.2).

3.7.2 Sequential rough handling. The cartridge shall be

capable of withstanding the following rigors of rough handling

and transportation:

Secured-cargo vibration test

Loose cargo test

2.13 meter drop test

12.20 meter drop test

3.7.3 Long term high temperature storage. The cartridge

shall be safe to store and fire (no critical defects as defined

in Table VI) after being subjected to 30 days of continuous

heating at 63�C � 1�C. The reliability of the cartridge (when

compared with the reliability obtained at ambient temperature's

function and casualty testing for the requirement in 3.6.1) shall

not degrade by more than 5 percent (see 6.7.2), and the cyclic

rate shall not change by more than 15 percent, when the cartridge

is subjected to continuous heating.

3.7.4 Long term low temperature storage. The cartridge

shall be safe to store and fire (no critical defects as defined

in Table V) after being subjected to 30 days continuous cooling

at -35�C � 1�C. The reliability of the cartridge (when compared

with the reliability obtained at ambient temperature's function

and casualty testing for the requirement in 3.6.1) shall not

degrade by more than 5 percent (see 6.7.2) and the cyclic rate

shall not change by more than 15 percent when the cartridge is

subjected to continuous cooling.

3.7.5 Thermal shock. The cartridge shall exhibit no

evidence of corrosion and shall function in the M60 and M240B

machine gun, after exposure to alternately high and low

temperature extremes.

3.7.6 Temperature humidity. The cartridge shall be safe to

fire (no critical defects as defined in Table VI) after being

subjected to a 10-day temperature/humidity cycle.

3.7.7 Sand and dust. The cartridge shall be safe to fire

(no critical defects as defined in Table VI) after being

subjected to sand and dust conditions.

3.7.8

Salt spray (fog) exposure.

The cartridge shall be