MIL-DTL-32505
APPENDIX B
B.3.5 Witness plate. A thin sheet located behind and parallel to the ballistic test sample which
is used to detect penetrating projectiles or spall.
B.4 REQUIREMENTS
B.4.1 Resistance to penetration. The minimum required V50 ballistic limit shall be in
accordance with the values shown in tables B-I through B-VII.
B.5 TESTS
B.5.1 Ballistic tests. Testing shall be in accordance with MIL-STD-662, V50 Ballistic Test
for Armor, except that nothing in this procedure shall be construed to supersede or invalidate
the requirements of this specification.
B.5.1.1 Temperature Conditioning. Prior to the test, the test item(s) shall be temperature
conditioned at least eight hours. Thermostatic control shall be such that the average
temperature of the item during the test shall be 72 ± 15°F (22 ± 8°C).
B.5.1.2 Protection ballistic limit, BL(P).
B.5.1.2.1 Normal circumstances. The BL(P) shall consist of an equal number of fair impact
complete and partial penetration velocities attained by the up-and-down firing method. All
BL(P)'s shall be computed using the highest partial penetration velocities and the lowest
complete penetration velocities. Firing shall continue until either a 4-round BL(P) having a
maximum velocity spread of 60 fps or a 6-round BL(P) having a maximum velocity spread of
90 fps has been attained, whichever comes first in the normal sequence of firing. If both
occur simultaneously, the 6-round BL(P) shall be reported.
B.5.1.2.2 Large zone of mixed results. In the event that the zone of mixed results (difference
between the high partial penetration velocity and the low complete penetration velocity, the
PP[P] velocity being higher than the low CP[P] velocity) exceeds 90 fps, the firing data shall
be compared with the specification minimum ballistic requirements. If the lowest complete
penetration velocity is equal to or above the minimum specified ballistic limit velocity for the
plate thickness, the ballistic limit shall be computed on the basis of 4- or 6-rounds using the
smallest possible velocity spread. If the lowest complete penetration velocity is below the
minimum allowable ballistic limit velocity, then testing shall continue until a 10-round
ballistic limit has been attained using the smallest possible velocity spread. Ten-round
ballistic limits shall be reported as agreed upon between the contractor and procuring activity.
B.5.1.2.3 Reduction of large velocity gap in borderline cases. If the ballistic limit, which has
been determined, is within ± 10 fps from the minimum allowable ballistic limit and a gap
exists which is greater than 25 fps, then another round, or rounds, shall be fired to reduce the
gap to 25 fps or less. The ballistic limit shall then be recomputed using the above criteria.
The recomputed BL(P) shall be reported as the BL(P) of the plate (in borderline cases, a
reduction of the gap between the high partial penetration velocity and the low complete
velocity should result in a better evaluation of the BL(P)).
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