Part II of "Requirements for replacements of currently issued 5.56 M-855 and 7.62 M-8

[JASmith]

Joe, why a single (relatively thick) steel plate for threshold, but spaced, thin steel sheets for objective? Shouldn't both requirements use the same 4498 target?

BTW, this reminds me of something I learned in past testing. Penetration of spaced (thin) steel is different than for a thick steel plate. Example: 9mm Ball punched through eight (8) thin steel sheets, but barely dented a 3.5mm thick plate.

The full STANAG target at 45 degrees is significantly more challenging than the single 3.5mm (10 gauge) steel plate face-on. The reason is the angle of impact initiates rotation of the bullet (tipping) and the gap gives time for the bullet to rotate. The second barrier makes it more acute, and the third being a little thicker might even deflect a bullet with marginal characteristics.

Recall that the purpose of the threshold is to force a minimum mass and velocity combination for the caliber. We can get by with the OTM bullets on the single plate, because they behave better on this kind of target than on the spaced plate.

Hence the objective targets force improved bullet design on barrier penetration with a rational starting point for bullet weight.