First off, for those of you (like your author) who are confused, "OTF" refers to "Open-Tip Frangible," not "Out The Front" like in the automatic knife community. It refers to the projectile construction of the 62-grain bullet.
While the rest of HPR's BlackOps line are pistol calibers that are light-for-caliber (150-grain .45 ACP, 85-grain 9 mm and 105-grain .40 S&W), the .223 Rem. offering is a standard 62-grain variant. Designed to work in rifles with 1:7-inch to 1:9-inch twist rates (pretty much all AR-barrels), these nickel-cased rounds are engineered for maximum energy transfer on target.
HPR designed the Black Ops line to be one of the most operational personal defense rounds available on the market today. This ammunition meets the lead-free requirements of California, featuring a lead-free powdered metal alloy core that delivers mass force trauma with reduced recoil.