RE: Is a 223 to small for deer?
My girlfriend shoots a Mini-14 .223 and she has killed 2 deer each year the last 5 years. I sight it in for her at 100 yards and it is very accurate to that distance. I doubt she would ever take a shot that long though. Most of the time they go down on the spot or just a short run. This year we had to track one maybe 50 yards into the brush, but I've had to do that using my .270. It is a fine gun for deer with proper shot placement and short to mid range shots.
I saw a thread a while back about using .410 slugs and there were those who were about ready to fight to defend the .410 for deer hunting. If a .410 is OK, a .223 is better.