Uses
The .223 Remington is one of the most common rifle cartridges in use in the United States, being widely used in two types of rifles: (1) varmint rifles, most of which are bolt action and commonly have 1-in-12 rifling twist suitable for bullets between 38 to 55 grains (2.5 to 3.6 g), and (2) semi-automatic rifles such as the AR-15 and the Ruger Mini-14, which are commonly found to have twist rates of 1-in-7, 1-in-9, or 1-in-8. (Most modern AR-15s use 1-in-9 which is suitable for bullets up to 69 grains / 4.5 grams or 1-in-7 which is suitable for slightly heavier bullets, but older M16's used 1-in-12 twist rates, making them suitable for use with bullets of 55 grains / 3.6 grams.) The semi-automatic rifle category is often used by law enforcement, for home defense, and for varmint hunting. Among the many popular modern centerfire rifle cartridges, .223 Remington ammunition is among the least expensive and is often used by avid target shooters, particularly in the "service rifle" category or 3 gun matches. The .223 is also used in survival rifles.
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