I recently picked up a box of Norma “Black Diamond” .45acp ammo, after looking for both the 9mm and .45 variants for some time. I thought the box and related info were interesting:
On the box end-label, this one was originally a .308 Winchester-Match box, and it has a .45acp overlabel from either Norma or Black Hills where it was loaded. I think the Black Diamond line was originally all rifle calibers, and the pistol calibers were an afterthought for the self-defense market?
The patent number listed on the back of the box is circa 1984 from a California applicant, and it just covers the method for applying a molybdenum-disuplhide coating to bullets:
As far as I can tell these are just typical +P jacketed hollow-point bullets with small perforations near the point, and which are coated in moly. The “matchgrade” attributes are apparently just the moly coating and maybe powder or primer selection, but there’s no info on those specifics on the box.