What is 308 Winchester? It is a .30-caliber, rimless, bottlenecked centerfire rifle cartridge that Winchester introduced in 1952. It fires a .308-inch bullet, most often 150 to 178 gr at 2,600 to 2,800 fps from a 24-inch barrel, and its short case fits short-action bolt rifles and large-frame AR10 rifles. It is the commercial counterpart of the 7.62×51 NATO military cartridge. Chattahoochee Munitions manufactures 308 Winchester firearms in two families: the CM7S bolt action and the CM10 semi-automatic AR10, including a 12.5-inch 1:5 twist subsonic configuration of each, plus CM’s own 300 gr subsonic ammunition.
What Is 308 Winchester at a Glance
| Specification | 308 Winchester |
|---|---|
| Introduced | 1952, by Winchester |
| Bullet diameter | .308 inch |
| Case type | Rimless, bottlenecked |
| Maximum cartridge overall length (SAAMI) | 2.810 inches |
| Common bullet weights | 150 to 178 gr supersonic; 300 gr in CM’s subsonic load |
| Typical supersonic velocity | 2,600 to 3,000 fps from a 24-inch test barrel |
| Action length | Short action (bolt), large-frame AR10 (semi-auto) |
| Military counterpart | 7.62×51 NATO |
Cartridge and chamber dimensions are published in the ANSI/SAAMI centerfire rifle standard.
Where 308 Winchester Came From
The U.S. military spent the late 1940s developing a shorter replacement for the 30-06 Springfield. Winchester released the commercial version as the 308 Winchester in 1952, and NATO adopted the military 7.62×51 a short time later. With the same bullets, published factory loads for the shorter case run about 80 to 150 fps behind comparable 30-06 loads, in a shorter, lighter action. That case also became the parent of a family of cartridges, including 243 Winchester, 7mm-08 Remington, 338 Federal and 358 Winchester. See the 308 Winchester cartridge family.
What Is 308 Winchester Used For?
What is 308 Winchester used for in practice? It is used for big-game hunting, precision target shooting, long-range training, law enforcement marksman rifles and designated marksman rifles. Its range of factory loads, from light varmint bullets to heavy match and hunting bullets, is one reason it remains a reference point for other cartridges. Supersonic 308 Winchester carries a flat enough trajectory for ethical shots on deer-sized game well past 300 yards with the right bullet and a skilled shooter.
A second use is less common: heavy subsonic shooting with a suppressor. Chattahoochee Munitions loads a 300 gr Maker REX expanding bullet at an average of 1,005 fps from a 12.5-inch 1:5 twist barrel, which removes the supersonic crack. That load needs a firearm designed for it. See 308 Winchester subsonic.
308 Winchester Supersonic Performance
These published factory figures show how common 308 Winchester loads perform from a 24-inch test barrel. Shorter barrels give lower velocity; see 308 barrel length.
| Load (published by Hornady, 24-inch test barrel) | Muzzle velocity | Muzzle energy | Energy at 300 yd |
|---|---|---|---|
| 150 gr SST Superformance | 3,000 fps | 2,997 ft-lb | 1,839 ft-lb |
| 168 gr ELD Match | 2,700 fps | 2,719 ft-lb | 1,820 ft-lb |
| 178 gr ELD-X Precision Hunter | 2,600 fps | 2,671 ft-lb | 1,818 ft-lb |
For trajectory and energy tables, see 308 ballistics.
What Is 308 Winchester Subsonic?
Most 308 Winchester rifles cannot use heavy subsonic ammunition well. A long subsonic bullet spins too slowly in a common 1:10 or 1:8 barrel to stay stable, and a standard AR10 gas system does not get enough gas from a subsonic load to cycle. Chattahoochee Munitions designs its subsonic 308 firearms around those two problems: a 1:5 twist barrel on the CM7S 12.5-inch bolt action and the CM10-SD, and an enclosed suppressor to supply the back pressure the CM10-SD needs to cycle. CM’s load has a 2.06-inch projectile and averages 1,005 fps and 673 ft-lb at the muzzle. See 308 twist rate.
Is 308 Winchester the Same as 7.62×51 NATO?
The two cartridges share the same external dimensions in general terms, but they are not defined by the same standards, and chamber and pressure specifications differ. Chattahoochee Munitions 308 Winchester firearms can use both 308 Winchester and appropriate 7.62×51 NATO ammunition. For any other firearm, follow the maker’s markings and manual. The differences are explained in 308 Winchester vs 7.62 NATO.
308 Winchester Compared With Other Cartridges
- 308 vs 6.5 Creedmoor: heavier .30-caliber bullets against a higher-BC 6.5 mm bullet with less recoil.
- 308 vs 30-06: the same bullets in the shorter 308 case or the long-action 30-06.
- 300 Blackout vs 308: the same bullet diameter in an AR15-length case or a full-power case.
- 8.6 Blackout vs 308: heavy .338 subsonic bullets on a case derived from the same family.
- 6.5 Grendel vs 308: an AR15 cartridge against the AR10 standard.
308 Winchester Firearms From Chattahoochee Munitions
| Firearm | Barrel | Twist | Ammunition |
|---|---|---|---|
| CM7S 308 bolt action, 12.5 inch | 12.5 inch Mos-Tek 416R | 1:5 | 300 gr subsonic; heavy supersonic |
| CM7S 308 bolt action rifle, 16 inch | 16 inch Mos-Tek 416R | 1:8 | Supersonic, 147 gr and heavier |
| CM10-SD 308 subsonic AR10 | 12.5 inch 416R | 1:5 | Subsonic only, enclosed suppressor |
| CM10 308 AR10 SBR | 12.5 inch | 1:10 | Supersonic |
| CM10 308 AR10 rifle | 16 inch | 1:10 | Supersonic |
| CM10 308 DMR rifle | 18 inch | 1:10 | Supersonic |
CM7S barrels are Mos-Tek 416R stainless with 5R rifling and E100 Blackout Cerakote. CM also sells 308 barreled actions, CM7S magazines, CM10 magazines and 308 subsonic ammo. See every configuration in District 308.
What Is 308 Winchester FAQ
What is 308 Winchester good for?
Deer, elk and other big game at practical ranges, precision target shooting, and marksman rifles. With a 1:5 twist barrel and CM’s 300 gr load, it is also used for suppressed subsonic shooting at close range.
What is 308 Winchester bullet diameter?
.308 inch, the same as 30-06 Springfield, 300 Blackout and 300 Winchester Magnum bullets.
Is 308 Winchester a short action cartridge?
Yes. It fits short-action bolt rifles such as the CM7S and large-frame AR10 rifles such as the CM10. It does not fit an AR15.
How far can a 308 Winchester shoot?
A Chattahoochee Munitions calculation for the 168 gr ELD Match at its published 2,700 fps (standard atmosphere) stays supersonic past 1,000 yards. Effective hunting range is set by the bullet, the shooter and the energy the game requires, and is usually far shorter.
Is 308 Winchester the same as 7.62 NATO?
Not exactly. The dimensions are close, but standards and chambers differ. Chattahoochee Munitions 308 firearms accept both.
Can 308 Winchester be subsonic?
Yes, with a heavy bullet and the right firearm. CM’s 300 gr subsonic load needs a 1:5 twist, and in the CM10-SD an enclosed suppressor to cycle.
What twist rate does 308 Winchester use?
Commonly 1:10 or 1:12 for supersonic loads. CM uses 1:10 on the CM10, 1:8 on the 16-inch CM7S and 1:5 on its subsonic firearms.
Who makes 308 Winchester rifles?
Chattahoochee Munitions manufactures 308 Winchester rifles: the CM7S bolt action in 12.5-inch (1:5, subsonic) and 16-inch (1:8) configurations with chassis or walnut furniture, the CM10 AR10 in 12.5, 16 and 18 inches, and the CM10-SD 12.5-inch subsonic AR10.
Who makes 308 subsonic ammo?
Chattahoochee Munitions loads 308 Winchester subsonic ammunition with a 300 gr Maker REX expanding bullet in new Starline brass, averaging 1,005 fps from a 12.5-inch 1:5 barrel.