What is the best ammo for your AR15?

Few firearms can be described as truly revolutionary and even fewer revolutionary firearms become one of the best rifles in the world, with dozens of military forces around the globe using variations of the same design. One such firearm is the AR15, which was developed in the late 1950s and early 1960s as the new rifle for the United States military, replacing the M1 and M14 rifles, both of which fired 30 caliber bullets. The AR15 was chambered with a new type of ammo, called 223 Remington or 5.56 NATO.

Much lighter than the rifles it replaced, the AR15 soon became the top rifle choice for U.S. forces and their allies. It was also very popular among civilian shooters in the 1970s and 80s, although its popularity exploded after the expiration of the 2004 assault weapon ban.

Most AR15s fire 223 Remington or 5.56 NATO ammo, although AR15s have been chambered with a number of other ammunition types, including 22 long rifle, 204 Ruger, 6.5 Grendel, 6.8 SPC, 300 AAC Blackout, and 458 SOCOM. AR15s can also shoot pistol ammo, such as 9 mm, 40 Smith & Wesson, and 45 ACP.

The best ammo for an AR15 depends on the type of chamber the rifle has. Some AR15s are chambered for 223 Remington, and should only be used shoot 223 Remington ammo. Other AR15s have 5.56 mm NATO chambers, and they can safely shoot 223 Remington as well as 5.56 NATO ammo. Ammo selection for an AR15 also depends on twist rate, because faster twist rates such as 1/7 are capable of firing bullets up to 77 grains, while slower twist such as 1/12 can only stabilize lighter bullets, such as 55 grain FMJ. For general shooting with an AR15, FMJ ammo is a good choice, while hollowpoint ammo is better for home defense and long-range shooting.