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|  MIL-C-46409D (AR)
APPENDIX "D" (CONT'D)
40.3.2.10 The piston is then removed from the piston hole. The knockout tool is then used
to force the obturating cup from the piston hole into the chamber. The obturating cup is then
removed from the chamber using a cleaning rod with a dry cleaning patch attached.
40.3.2.11 Continuous air cooing should be used on the bard; however, if air cooling is not
available, firing should be regulated so that one cartridge is fired every thirty (3) seconds. At no
time shall the exposed metal surface of the test barrel become too hot to grasp with the bare
hands (approximately 140F).
40.3.2.12 The copper pressure cylinders whose identities are maintained throughout the test
are measured in the same manner as they were prior to the test. The difference in length (set in
inches) is then applied to the primer tarage table, and the corresponding PSI is obtained and
recorded on the report form. The chamber pressure correction shall then b obtained as specified
in 30.2.
40.3.2.13 If the average chamber pressure of the standard (reference) cartridges is not
within 3500 PSI of the official assessed value, the test barrel shall be removed from the test,
another test barrel substituted and another series of standard (reference) cartridges fired. If this
firing fails to produce satisfactory results, the cause thereof shall be identified and eliminated
before resuming the test.
40.3.2.14 After the barrel has cooled to ambient temperature, warming (fouling) shots shall
be fired in accordance with 40.3.2.1.
40.3.2.1.5 The test cartridges shall then be fired following the procedure as specified in
40.3.2.2 through 40.3.2.9.
40.3.2.16 The copper cylinders used with the test cartridges are measured in the same
manner as they were prior to the test. The chamber-pressure readings shall be placed on the test
sheet in such a manner that the velocity and chamber-pressure of each shot is identifiable. The
chamber-pressure correction obtained with the reference cartridges shall be applied to the
average chamber-pressure of the test cartridges, as specified in 30.2.
40.3.217 If any of the personnel conducting the test observes any abnormality that may
invalidate the velocity or pressure measurements, the circumstances shall be reported
immediately through appropriate supervisory channels and the test suspended until instructions
are received from proper authority. If any result appears abnormal, even though the possible
cause cannot be immediately assigned, the circumstances should be reported immediately for
investigation and decision by proper supervisory authority.
50.0 RECORDING OF DATA
50.1 Results of both standard (reference) cartridges and test cartridges should be recorded
directly on the test sheet form. Velocities shall be recorded to the nearest FPS; chamber-pressure
shall be recorded to the nearest 100 PSI.
50.1.1 Standard (reference) cartridges - The individual velocities and chamber-pressures,
average velocity and chamber-pressure and extreme variations of velocity and chamber-pressure
shall be recorded.
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