^x2
I'm not sure you need any other posts after this one little_airwolf~I agree with every word of it myself. NR .223 semis that are 1/2 worth a damn are very pricey things and even then, I've never heard of (or really bothered to search-out) one that shot as well, unmodified, as a decent off-the-shelf bolt gun. Ammo is also a big part of the equation, as stated already, so a bolt gun won't digest as much AND deliver the lead where it ought to be going. I'd strongly suggest you start with a bolt action.
This is the .223 I use for varmint hunting, and it's a better shooter than I am.

On my best days, I've put 5 shots through 1 ragged hole @ 110 yards with it using Hornady 55gr. V-max. (my preferred varmint round) Hard (for me) to be tempted by a Kel-Tec when I know it won't hold a candle to how this shoots.