Shooting Illustrated by Richard Mann March 1, 2021
Throughout history, several firearms have become inexorably linked to a single cartridge. Colt’s 1911 will always be associated with the .45 ACP. When you think of lever-actions, you think of the .30-30 Win. And, the AR-15 is forever tethered to the .223 Rem./5.56 NATO.
Of course, that isn’t exactly correct, is it? Today, you can get 1911s and lever guns chambered for a variety of cartridges. The same holds true for the AR-15. But, is there a “best cartridge†for what has become known as the modern sporting rifle (MSR)? The answer is complicated.
With the arrival of the new millennium, the AR-15 saw many modular innovations, and new cartridges compatible with the platform started popping up. Counting wildcat cartridges, there may now be as many as 50 options. However, from a SAAMI (Sporting Arms and Ammunition Manufacturers Institute)-approved standpoint, a practical list includes the .223 Rem., 22 Nosler, 224 Valkyrie, 6 mm ARC, 6.5 Grendel, 6.8 SPC, .300 BLK, .300 HAMR, .30 Rem. AR, 7.62x39 mm, 350 Legend, .450 Bushmaster and .458 SOCOM.
Selecting the best of this bunch is dependent on what you want to shoot, as an AR-15 can be used for many things. Do you want to use your AR-15 for one thing, several things or everything? One way to compare AR-15 cartridges is to consider external ballistics and look at downrange performance. This, of course, never presents a comprehensive comparison; other things matter.
More:
https://www.shootingillustrated.com/articles/2021/3/1/the-complete-guide-to-ar-15-cartridges
