One question we get frequently here is "What should I buy for my first AR-15?" A rifle we often suggest is the Sig Sauer M400 in 5.56mm. This rifle is more basic in its layout compared to some which is great for a first AR-15. It features a 16" barrel with a twist rate of 1:7 (so it will shoot the heavier 5.56mm bullets very accurately), a collapsable stock, and built in single-point sling quick attachment points. It's available with mil-spec furniture, Magpul MOE furniture, or a quad-rail system. Sig Sauer has one of the best reputations for building a quality gun, and they really delivered a great carbine for just about any use.