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

[stanc]

Requirement 2: Barrier Penetration

Threshold: Steel plate defeat
[INDENT]Perforate a 3.5 mm (10 gauge) steel plate at a lower velocity than with a 150 gr .308 bullet when using an open tip match bullet in both calibers.[/INDENT]
Rationale: This threshold requirement establishes a relationship between bullet velocity, mass and diameter when standard bullets are used. The thickness specified is approximately the total thickness obtained when the three plates of the target defined in STANAG 4498 (NATO Medium Truck).

Objective 1: Spaced Steel plate defeat
[INDENT]Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate the STANAG 4498 target at when the bullet impacts at 45 degrees from normal when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.[/INDENT]

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.