I had recently just bought my first AR. I started with a spikes lower, and all of the other Magpul goodies. I was searching around for an upper with a quad rail system, and was looking at a YHM diamond series. Then my buddy that works at our local gun range suggested the 516 to me, so I went for it. I have had no complaints on it so far. A bit heavy for my gf and son, but I like bulky things. The 516 shoots like a charm, little recoil, and after about 500 rounds through it, I decided to take the BCG out, pretty amazing design on gas systems, as there was very little carbon build up.