I think the ammunition that isn't being sold was just hot FMJ. All the armor-piercing claims really pertain to the law-enforcement-only loads, anyway (which are hard, sharp, and pointy); with civilian ammo, it will NOT penetrate a level II or IIIA vest, per the BATFE and the Fraternal Order of Police. A variety of JHP loads and possibly target rounds are available, IIRC.
The Brady Bunch put out a video purporting to show it defeating a vest, but if you watch the video the narrator says it's a level IIA, which is not even rated to stop .357 magnum.
The FiveSeven is a neat gun, but it's basically just a centerfire .22 WMR optimized for a handgun-length barrel, not some magical wonder bullet.