Ten Popular Rifle Calibers: A Plain-English Map of the Mainstream Shelf

Walk into a rifle shop and the same handful of cartridges turn up again and again. They fall into four groups: AR-15 cartridges, deer-class standards, magnums and old military rounds. Knowing the groups makes the rest of the shelf easy to read.

AR-15 cartridges

The .223 Remington is the default, and its loads are at 223 ammo.

The 224 Valkyrie, introduced by Federal in 2017, is a long-range .22 for the same platform, and its 90-grain loads are at 224 valkyrie 90 grain ammo.

The 300 Blackout, standardized in 2011, is a short-range cartridge that works well in short barrels and with suppressors. Its loads are at 300 blackout ammunition.

Deer-class standards

The .243 Winchester, a .308 case necked down in 1955, is the dual-purpose varmint and deer cartridge, and soft-point loads are at 243 soft point ammo.

The .270 Winchester dates to 1925 and made its name as a flat-shooting deer and elk cartridge. It is chambered in a wide range of rifles, so anyone who wants to buy 270 ammo is shopping for a cartridge with a very long track record.

The .308 Winchester, from 1952, is the short-action all-rounder, and its loads are at 308 ammo for sale.

The .280 Ackley Improved is a sharper-shouldered, higher-capacity version of the .280 Remington, a handloader's favorite that factory makers now load, and its loads are at 280ai ammo for sale.

Magnums

The 300 Winchester Magnum, a belted cartridge from 1963, is a long-established .30 magnum, and its 180-grain loads are at 300 win mag 180 grain ammo. The 300 WSM, from 2001, gets similar speed from a short, fat, beltless case, and polymer-tip loads are at 300 wsm polymer tip ammo.

An old military round

The .303 British was adopted in 1888 for the Lee-Metford rifle and served the British Empire for more than half a century. Prvi Partizan's loads are at prvi partizan 303 british ammo.

How to use the map

Start with the rifle, not the cartridge. The chambering is stamped on the barrel, and the name on the box has to match it exactly. The rest of this series takes the same ten cartridges one angle at a time.

Mainstream does not mean interchangeable. Match the marking on your barrel to the box exactly, and confirm current stock and state shipping restrictions before ordering.