probably an m16 for a primary weapon, and a barret for a secondary weapon. I like to be able to throw a lot of rounds down steam, yet have a powerful sniper rifle!
My dad and I built 2 AR-15 (M16 Without 3 Round Burst). One has a high powered scope and the other one has a tactical handle. We also have a digital camoflauge Ak-47. I love those guns.