w/INT. AMENDMENT 4
BALLISTIC TESTING OF ARMOR, STEEL PLATE, WROUGHT, HOMOGENEOUS
A.1.1 This appendix covers the requirements for ballistic testing of wrought homogeneous steel
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 APIT. 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 has 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
A.2.5 Gap. 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.