the first time i saw this caliber was on Sons of Guns when they built the .458 SOCOM on the AR platform. LOVED IT!!!! now, i see Rock River Arms offers a complete upper assembly compatible with any lower assembly, the rounds even fit in the same 30rd mags u would use for .223/5.56. i'm thinking, i would love having a .458 AR sitting in the closet for home protection, but at $700 for the upper, do you think it's worth it? and from what i read, it's about $4 per round?? would i be better off just getting a .40 or .45 cal hand gun and save the money?? what do you guys think?? just the idea of having such a high caliber AR that people don't see everyday, to me, may be worth the money alone....