Most rifle ammunition is general purpose: a bullet that shoots accurately, hits hard enough and suits a sensible range of rifles. Two kinds are deliberately not. Subsonic .308 and frangible .223 are built for narrow jobs, and using them for anything else is how buyers end up disappointed.

Frangible: a bullet that is meant to break

A frangible bullet is made from compressed metal powder, often copper or a copper-and-tin blend, and it is designed to disintegrate when it strikes something hard. The aim is to cut ricochet and splash-back, so the design is used on steel targets and at close-quarters training ranges. Loads like the ones behind frangible 223 ammo are usually lead-free and lighter than ball, and they are not hunting bullets, because they are built to break up rather than to expand and penetrate.

Ranges set their own ammunition rules. Ask before you shoot frangible, steel-core or steel-case rounds, and expect the point of impact to differ from your ball ammunition, so confirm the zero.

Subsonic: a bullet that is meant to stay quiet

Sound travels at about 1,100 feet per second at sea level, and a bullet that outruns it makes its own sonic crack. Subsonic .308 loads use heavy bullets, typically around 200 grains, loaded down to stay under that speed so that a suppressor can do its job. Those loads are grouped at subsonic 308 ammo.

The trade-offs are real. A 200-grain bullet at around 1,000 feet per second drops quickly past 100 yards, and a semi-automatic rifle may not cycle on such a light charge unless its gas system is set up for it.

General purpose, for comparison

Ordinary practice ammunition is full metal jacket. Winchester's 55-grain .223 loads, at winchester 223 55 grain ammo, are typical. Its 5.56 version, at winchester 5.56x45 55 grain ammo, is the same idea built for NATO-pattern chambers.

The 5.56 range includes other brands too, such as Aguila at aguila 5.56 ammo.

Hornady's .223 loads, at hornady 223 ammunition, lean toward polymer-tip and match bullets. The plain FMJ in the M193 pattern is what you get at fiocchi m193 ammo.

In .308, hunting rifles add Barnes' polymer-tipped all-copper loads, at barnes 308 polymer tip ammo. Remington's Core-Lokt soft points, a design in production since 1939, are among the loads at remington 308 ammo for sale.

Even the 5.45x39 has standard and specialty versions. Hornady's V-MAX load, at hornady 5.45x39 ammo, is the polymer-tip alternative to the usual FMJ.

Specialty ammunition is built for specific equipment and ranges. Confirm that your rifle, suppressor and range suit the load, and confirm current stock and state shipping restrictions before ordering.