Of course, you probably expected to see the AR-15 on his list. The AR-15 is the most popular rifle in the United States and also long been at the center of controversy politically speaking. The AR-15 is basically a semi-automatic only version of the military’s M4 and M16 carbines and rifles, which are selective fire. It fires the 5.56x45mm NATO round usually, but is also chambered for a number of other cartridges as well. ARs that fire the .308 Winchester or other intermediate rounds are referred to as the AR-10. AR-15s are known for being easy to shoot, ergonomic, and with limited recoil. They can be a great choice for tactical training, home defense use, or hunting.