That's exactly my point about this law... the TC Contender in .30'06 and the MRI Lone Eagle in .308 (the picture I posted) are both legal to carry, since they both fire projectiles measuring .308"... well under the .45 requirement, no matter how you interpret it. However, they are both far more powerful and have far more penetration than a .50 GI, or even a .50 AE or .500 S&W. No vest short of a full ceramic plated one would stop them.
No, they aren't legal- read the full text:
Sorry, most folks would be doing superbly well to "control" a heavy barrelled Riger MkII when someone was shooting back. Let's not get our panties in a wad- what is the most powerful round that can be fired most accurately, rapidly, under pressure? Yup, 9mm/.45, maybe .40 for those Professional Enough...§211289.19. Restricted bullet and body armor defined.
As used in Sections 1289.20 through 1289.22 of this title and Section 2 of this act:
1. "Restricted bullet" means a round or elongated missile with a core of less than sixty percent (60%) lead and having a fluorocarbon coating, which is designed to travel at a high velocity and is capable of penetrating body armor; and
2. (a bullet capable of penetrating...)"Body armor" means a vest or shirt of ten (10) plies or more of bullet resistant material as defined by the Office of Development, Testing and Dissemination, a division of the United States Department of Justice.
Added by Laws 1982, c. 193, § 1, emerg. eff. April 22, 1982. Amended by Laws 1992, c. 216, § 1, eff. Sept. 1, 1992.
Title 21, ss21-1289.19: here.