MIL-DTL-12560 Armor Plate, Steel, Wrought, Homogeneous \(For Use In Combat-Vehicles And For Ammunition Testing\)This specification covers wrought-steel homogeneous armor plate for ordered thicknesses from 0.098 inch \(2.5 mm\) up to an ordered thickness of 6.000 inches \(152.4 mm\), inclusive, for use in combat-vehicles and for ordered thicknesses from 0.250 inches \(6.35 mm\) up to an ordered thickness of 12.000 inches \(304.8 mm\), inclusive, for use in proof and acceptance testing of armor defeating ammunition \(see 6.1, 6.2, and 6.3.3\).

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MIL-DTL-12560K (MR)

APPENDIX A

BALLISTIC TESTING OF ARMOR, STEEL PLATE, WROUGHT, HOMOGENEOUS

A.1 SCOPE

A.1.1 This appendix covers the requirements for ballistic testing of wrought homogeneous steel

armor plate.

A.2 DEFINITIONS

A.2.1 Fair impact.

A.2.1.1 Caliber .30 AP through 20 mm tests. A fair impact is an impact resulting from the striking

of the test plate by a projectile in normal flight (no excessive yawing or tumbling) and separated

from another impact or the edge of the plate, hole, crack or spalled area by an undisturbed area at

least two test projectile diameters.

A.2.1.2 57 mm AP and larger calibers. A fair impact is an impact resulting from the striking of the

test plate by a projectile in normal flight (no yawing or tumbling) and separated from another

impact or from the edge of plate, hole, crack or spalled area by at least one test projectile diameter

of undisturbed area.

A.2.2 Witness plate. A witness plate is normally a 0.014 inch thick sheet of 5052 aluminum alloy

(or a 0.020 inch thick sheet of 2024-T3 aluminum alloy placed 6 inches (+ 1/2 inch) behind and

parallel to the test plates or other ballistic sample.

A.2.3 Complete penetration, protection, CP (P).

A.2.3.1 For caliber .30 M2 AP through 20 mm M602 API-T. A protection complete penetration

occurs when the projectile or one or more fragments of a projectile or plate pass beyond the back

of the test plate and perforates the witness plate.

A.2.3.2 For projectiles larger than 20 mm. A protection complete penetration occurs when one or

more fragments of a projectile or plate have been ejected from the rear of the plate as determined

by visual inspection.

A.2.4 Partial penetration, protection, PP (PI). A partial penetration is any impact that is not a

complete penetration.

A.2.5 Gap. A gap is the difference in velocity between the high partial penetration velocity and the

low complete penetration velocity used in computing the ballistic limit where the high partial

penetration velocity is lower than the low complete penetration velocity.

A.2.6 Protection ballistic limit, BL (P).