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|  MIL-C-46409D (AR)
APPENDIX "C" (CONT'D)
40.0 TEST PROCEDURE
40.1 Pre-firing (Preparation for test)
40.1.1 The required number of test cartridges and standard (reference) cartridges shall be
placed in a vertical position, primer-end down, in recessed holding blocks. The cartridges shall
be permitted to come to a temperature of 60 to 80 F prior to being placed in the temperature-
controlled room or contained The recessed holding blinks containing two series of cartridges
shall be placed in a temperature-controlled room or container in such a manner that all cartridges
arc subjected to a uniform temperate for a minimum of two hours, prior to firing. The
container or room shall be maintained at a temperature of 70F, 2 F, with a relative humidity
of 60 percent, 5 percent and be of sufficient capacity to allow free circulation of air.
40.1.2 The velocity-barrel assembly is assembled in the test fixture, on the mount. The
chamber and bore of the barrel are wiped dry. The barrel is then boresighted into position.
40.3.1 The velocity-barrel assembly shall be in accordance with the applicable drawings and
the following measurements shall be made before it is placed in service, after misfires, pierced
primers, flowbacks or whenever a part replacement has been made in the breech block assembly.
Limits
Firing-pin protrusion
.060" - 0.68"
.011" - .015"
Firing-pin indent
Headspace
.058" - .60"
40.1.4 Lumiline screens are checked for position. It is of the utmost importance that the
lumiline screens be placed in their proper position. Measurements must be accurate.
40.2 During firing.
40.2.1 Five(5) warmer (fouling) shots shall be fired. Velocity readings should be recorded
by the chronographer to assure that the velocity-measuring equipment is functioning properly.
40.2.2 The recessed holding block containing the required number of standard (reference)
cartridges is removed from the controlled temperature room or container and placed at a point
convenient to the technician, provided the temperature of the firing room is 70 F 5F.
Otherwise the cartridge shall be placed in an insulated box (five cartridges at a time) which has
been conditioned at 70F 5F, and the box placed at a point convenient to the technician. The
cartridges are then removed singly from the insulated box immediately before firing. If an
insulated box is not available, then the cartridges shall be removed singly from the controlled-
temperature room or container immediately before firing.
40.2.3 In order that the propellant shall be uniformly positioned from cartridge to cartridge
before firing, attention to detail is necessary in handling and cambering the cartridge.
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