I'm looking to buy my first AR and a few questions. I'm leaning towards a base model SW M&P15 ORC or Bushy ORC. I've heard good things about both and Stag as well. I'm looking for something I can shoot targets/range and also for HD. I'd just like something base model as I'm sure I'll be replacing parts at some point and don't want to go ape right off the bat. I was hoping to stick with .223 since ammo was cheaper and I'm sure I'll be shooting quite often. If I went with .556, do they make a .22 conversion kit so that I can plink at a small price? What is the difference in range for a .223 versus .556 round? That's also a deciding factor since I'd like to be able to shoot farther for targets. All in all, I'm looking for a base model (cheaper the better) good quality AR that I can make exactly what I want when I figure out what that finally is.