I personally own an AR-15 platform rifle of which is the Colt M4 carbine with matching magpul hand guard, foregrip, stock, and pistol grip. The rifle is of course chambered in .223/5.56mm NATO. I have a 4-16x40 scope mounted with 2 1" risers for hunting (took it hunting this last deer season and had a successful kill at 175 yards with one shot). Pretty good all around gun in my eyes havent had any complaints about it yet.
I've been wanting to get a decent rifle, but don't want to spen a lot of money...the only thing I have now is a Springfield 1911 Mil-spec. I love it...and feel bad for anyone that tries to get in to my house and harm my family. .45s make big holes! My cousin has an AR-15 that he drives 100 miles away to take marksman classes with a retired Ranger I believe.