the 10.5 inch barrel 223 with a 55 grain bullet at 2500 FPS or so indoors at spitting distance is interesting, but I got to think a 55 grain 223 at 3100 FPS within the same distance would produce slightly better results. The pistol caliber carbine in 45 ACP I am thinking real benefit would be a few dB's lower should you not be able to get your ear pro on. Just sayin is all. I don't dispute the effectiveness differences.
