Sounds like 223 is the way to go. Any recommendations on a decent middle of the road rifle(read inexpensive but decent, if such a thing exists). I won't use it enough to justify spending a ton, just need something reliable and accurate. Mainly be used for predators and varmints, with deer mixed in sporadically
Travis's gave sound advise on this.
Colt, upgrade the trigger when Rock River has one of their sales. President's day is coming up, so you might be able to find them for a good price then.
If you want to customize it, get one of the OEM models and pick the furniture you like.
Won't win you any matches, reliable, and will retain it's resell value.
If you get bit by the AR tinkertoy bug, you're starting with good parts.
