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Page Title:
Operating Procedure for the Ballistic Pressure Transducer |
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|  MIL-C-14858A (AR)
AMENDMENT 3
APPENDIX A
c. If the Assessed Values equals Actual Mean Value, no correction is applied to test
cartridge data.
A.4.4 The transducer Pressure Test barrel will be acceptable provided the mean velocity
and chamber pressure results obtained with the referenced cartridges are within 35 ft/sec., and
3,500 psi, respectively, of the assessed values.
A.4.5 It is required that informational charts be maintained, for record purposes, of
results from each test barrel in which reference cartridges are fired.
A.5. OPERATING PROCEDURE FOR THE BALLISTIC PRESSURE TRANSDUCER
A.5.1 The chamber pressure shall be determined by using acceptable ballistic pressure
transducers of the type specified in the appropriate Inspection Equipment List. Alternate designs
may be submitted to TACOM-ARDEC for approval prior to use.
A.5.1.1One transducer shall be used at the chamber location (case mouth) of the test
barrel.
A.5.2 The transducer shall have its sensitivity determined prior to the test and after
successive 120 + 20 cartridges are fired, at the pressure level of 50,000 psi. The transducer
sensitivity shall be expressed in units of picocoulomb per psi and shall be identified as being
determined at 50,000 psi. The method for determining the transducer sensitivity is detailed in
Annex 1.
A.5.3 After having determined the sensitivity for the transducer, the value shall be
compared to the value of the sensitivity obtained at the very last sensitivity determination. If the
sensitivity change since the last determination at the pressure level of 50,000 psi (if the
transducer will be used for measuring chamber pressure) is greater then + 2 percent or more than
+ 10 percent from the original calibration, the transducer shall be disqualified and shall be
unacceptable for further testing at that pressure level.
A.5.4 The sensitivity value to be used for testing shall be the most recent value obtained
for the pressure level that the transducer will be exposed to during the test.
A.5.5 A record shall be maintained of the sensitivity obtained for the transducer at the
50,000 psi pressure level as a function of the number of cartridges fired on each transducer. A
suggested format is shown at the end of Annex 1.
A.5.6 New transducers shall be completely tested for acceptability according to the
methods detailed in Annex 1.
6 (22)
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