MIL-DTL-19264C (OS)
previous group by approximately 100 ft/s or more is a conditioning round. Warming and conditioning
rounds may have unusual ballistics and the results, therefore, should be disregarded. These rounds are in
addition to those specified in subsequent paragraphs.
4.6.6.2 Gun performance tests. All ballistic testing shall be conducted using fleet-released 5-inch, 54-
caliber gun barrels which have met the acceptance criteria during proofing and which have a velocity loss
of 50 ft/s or less. The MK 45 Mod 1/2 gun system shall be used except for the charge weight probe and
validity tests. The non-test components (e.g.; case, primer, etc.) of the complete round of ammunition
shall be from one acceptable lot per component and the cartridge shall be assembled in accordance with
the applicable Naval Sea Systems Command propelling charge assembly drawing, 3208375 Charge,
Propelling, 5-inch MK 67 Mod 3 (See 2.2.2). Allowable deviations in propelling charge assembly may
include adjustment of charge weight/(PPD) as required to vary ballistic performance. The projectiles
shall be inert loaded and their weight shall be 70.0±0.1 pounds mass. The chamber volume resulting from
the projectile and propelling charge combination shall be representative of that of the fleet use
projectile/propelling charge combination. The ballistic test shall be performed on the preproduction and
production lot except that:
a. For the production sample, the test of 6.5 herein is mandatory.
b. For the production lot, the test of 6.5 herein shall be performed at the discretion of the
government when (1) the government deems the test necessary or (2) when the test
results of other parameters are marginal.
4.6.6.3 Charge assessment. Charge assessment shall be conducted using the firing programs described
below. Only one gun shall be fired each day and the velocities shall be corrected to the muzzle. The
cases, primers, and propellant for all propelling charges shall be conditioned at 90 ± 3° F for a minimum
of four (4) days immediately prior to assembly and shall be fired at 90 ± 3° F. Charges shall be loaded to
yield the packing depth within 0.4 inches of that determined in 4.6.5 for the charge weight to be fired.
The charges should be crimped, though the use of adhesive is not necessary. For the charge weight
validity firing program, the cartridges shall be reconditioned after assembly for a minimum of 48 hours at
90 ± 3° F prior to firing. For all tests, the cartridges shall be fired within five (5) minutes of removal from
temperature conditioning.
4.6.6.3.1 Charge weight probe. A probing round firing program shall be conducted in an instrumented
test mount to determine the estimated charge weight of the TP needed to match the projectile muzzle
velocity of the RP. The test shall consist of firing a series of RP and a series of TP rounds wherein the TP
charge and PPD are adjusted to vary projectile muzzle velocity and chamber pressure. Sufficient rounds
should be fired to obtain at least two rounds below and two rounds at or above the RP projectile muzzle
velocity. An estimate shall be made from the TP velocity-charge data of the TP charge weight required to
match the mean RP projectile muzzle velocity (3.8.1). If the estimated chamber pressure for the
estimated TP charge, as determined from the pressure-charge data, exceeds the maximum chamber
pressure limit of 3.8.2 by more than 1,350psi, the probing program shall be repeated. If the estimated TP
charge again has an estimated chamber pressure which exceeds the maximum chamber pressure by more
than 1,350psi, the lot of propellant shall be rejected without further testing.
4.6.6.3.2 Powder proof firings. A firing program shall be conducted in each of four gun barrels in the
automatic MK 45 Mod 1/2 gun system to determine the TP charge weight required to match the projectile
muzzle velocity for the RP. Three (3) charges at each of four (4) charge levels shall be fired in each gun
barrel. The first TP charge (C1) shall be that which was determined during the charge weight probe round
test to match the mean RP projectile muzzle velocity. The second charge (C2) shall be approximately 0.5
pounds mass less than C1 and the third charge (C3) shall be approximately 0.5 pounds mass greater than
C1. The fourth charge, or matching charge (MC), is that charge of the TP which is predicted to match the
RP projectile muzzle velocity in that gun on that day.
7
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business