CM 308 Subsonic Ammunition

Chattahoochee Munitions manufactures 308 subsonic ammunition, loaded for its own 308 Winchester firearms. Each cartridge uses a 300 gr Maker REX solid-copper expanding bullet in new Starline 308 Winchester brass, loaded to 2.79 inches overall. From a 12.5-inch 1:5 twist barrel it averages 1,005 fps with a 2.44 fps standard deviation over 10 rounds, measured by Chattahoochee Munitions, for about 673 ft-lb at the muzzle.

The 2.06-inch bullet needs a 1:5 twist. Chattahoochee Munitions designs two firearms around this load: the 12.5-inch CM7S bolt action, which fires it with or without a suppressor, and the CM10-SD subsonic AR10, which cycles it with an enclosed suppressor attached. It is not suited to 1:8 or 1:10 barrels or to conventional AR10 rifles.

308 Subsonic Ammunition

• CM 308 subsonic ammo, 300 gr Maker REX, 20 rounds per box

Firearms for This Load

• CM7S 12.5-inch 1:5: the 308 subsonic bolt action, the 308 compact hunting rifle and the 308 subsonic barreled action
• CM10-SD: the 308 subsonic AR10

Read 308 Winchester subsonic and 308 ballistics for the range card, and see every 308 Winchester firearm in District 308.

308 Subsonic Ammunition FAQ

Who makes 308 subsonic ammo?

Chattahoochee Munitions loads 308 subsonic ammunition with a 300 gr Maker REX expanding bullet for its CM7S 12.5-inch bolt action and CM10-SD subsonic AR10.

What twist rate does this 308 subsonic ammunition need?

1:5. Slower twists such as 1:8 and 1:10 do not stabilize the 2.06-inch bullet at subsonic speed.

Will it cycle in my AR10?

Chattahoochee Munitions has verified it only in the CM10-SD with an enclosed suppressor. Most AR10 rifles are set up for supersonic pressure and will not cycle it.

Is it good for hunting?

Yes, at close range. The Maker REX is designed to expand at subsonic speed; keep shots inside about 150 yards. See 308 for hunting.