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

[stanc]

Threshold: 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 a 3.5 mm (10 gauge) steel plate when using an open tip match bullet (E. g., Sierra Match King, Berger Match, etc.).[/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). The bullet selection is restricted to permit a near-standard comparison across calibers and to establish a minimum cartridge size for barrel length. The performance of the open tip match bullet on this target is presumed to match that of classic lead-filled full-metal jacketed bullets.

I dunno if it's a good idea to make that presumption. The more fragile tip construction of HPBT match bullets may well result in less penetration compared to FMJ, especially the (steel-tip) M855 round. However, if one could establish that penetration of, for example, 150gr .308 MatchKing is the same as 147gr M80 FMJ... If you're not going to compare candidate cartridges w/FMJ bullets to M80 and M855, might it be better to compare MatchKings (or Bergers, etc) in 5.56 and 7.62 to the new caliber?

FWIW, once upon a time I shot at a 3.5mm thick steel plate (of unknown hardness) at a distance of ~400 yards, using 7.62 M80 and 5.56 M193. The 7.62 punched through the plate; 5.56 merely dented it. Anyway, the point is that whomever might conduct such a test will need significantly longer than a 400-yd range to do it.

Concur with your objective requirements.