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|  MIL-C-14858A (AR)
AMENDMENT 3
"3.7 Chamber pressure. Chamber pressure testing shall be performed using either the
copper crush cylinder test method or the EPVAT test method after first having conditioned the
ammunition and the test apparatus for two hours at ambient (70F 2F). The test method
employed shall be recorded on the test results record.
3.7.1 Chamber pressure by the copper crush-cylinder test method. The average chamber
pressure of the pre-conditioned sample cartridges fired at ambient temperature shall not exceed
55,000 psi. The average of the SDs of chamber pressure for fifteen 20-round series shall not
exceed 2,000 psi. The test shall be conducted in accordance with 4.4.6.
3.7.2. Chamber pressure by EPVAT test method. The average chamber pressure of the
sample cartridges, conditioned at 70F , shall not exceed 65,000 psi. The average of the SDs of
chamber pressure shall not exceed 2,000 psi. The test shall be conducted as specified in 4.4.6."
PAGE 4
4.3.1.2, Delete in its entirety and substitute the following:
"4.3.1.2 Component parts. Unless otherwise specified, component parts shall be
homogeneous and of a size convenient to the contractor and inspected, tested and accepted by
the contractor. The cartridge lot shall contain:
a.
Cartridge cases from one unchanged process and one manufacturer.
b.
Bullets from one unchanged process and one manufacturer.
c.
Primers from one lot and manufacturer.
d.
Propellant from one lot and one manufacturer."
PAGE 10
4.3.3a, Line 6, Delete: "Sufficient cartridges shall be selected such that all testing (including
testing of second samples where applicable) can be performed."
PAGE 11
*
4.4.3.1, Quality Conformance Inspection,
Delete:
"Action time
50
1/
3.5
4.4.4
Velocity
300
3/
3.6
4.4.5
Chamber pressure
300
3/
3.7
4.4.6"
Substitute:
"Action Time
300
1/
3.5
4.4.4
Velocity
300
3/
3.6
4.4.5
Chamber Pressure
300
3/
3.7
4.4.6"
2
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