Chattahoochee Munitions manufactures complete 308 Winchester firearms on two platforms. The CM7S bolt action comes as a 16-inch 1:8 twist rifle for supersonic 308 and as a 12.5-inch 1:5 twist pistol or SBR for CM’s 300 gr subsonic load, in the CM7 chassis or with WOOX walnut furniture, plus CM7S barreled actions in both lengths. The CM10 AR10 comes in 12.5, 16 and 18-inch 1:10 twist configurations for supersonic 308 Winchester and 7.62×51 NATO, and the CM10-SD is a 12.5-inch 1:5 twist subsonic AR10 that cycles with an enclosed suppressor. Chattahoochee Munitions also loads its own 308 subsonic ammunition, and every complete firearm ships with one magazine.
District 308 is the 308 Winchester rifle home of Chattahoochee Munitions. The 308 Winchester is a short-action .30-caliber cartridge that drives 150 to 178 gr bullets at 2,600 to 3,000 fps for big game and precision shooting, and with the right twist rate it can fire a 300 gr bullet below the speed of sound for suppressed use.
What Is 308 Winchester?
308 Winchester is a rimless, bottlenecked .30-caliber rifle cartridge that Winchester introduced in 1952, the commercial counterpart of the 7.62×51 NATO military round. Its short case fits short-action bolt rifles and large-frame AR10 rifles, and it is the parent case of 243 Winchester, 7mm-08 Remington, 338 Federal and 358 Winchester. Read What Is 308 Winchester?
308 Winchester Specifications at a Glance
- Bullet diameter: .308 inch
- Maximum cartridge length: 2.810 inches
- Action: short-action bolt rifles and AR10 rifles
- Supersonic loads (Hornady published, 24-inch test barrel): 150 gr SST at 3,000 fps; 168 gr ELD Match at 2,700 fps and 2,719 ft-lb; 178 gr ELD-X at 2,600 fps
- Chattahoochee Munitions subsonic load: 300 gr Maker REX at 1,005 fps average and 673 ft-lb from a 12.5-inch 1:5 barrel
- Chattahoochee Munitions twist: 1:10 on the CM10, 1:8 on the 16-inch CM7S, 1:5 on the 12.5-inch CM7S and the CM10-SD
- Muzzle thread: 5/8×24 on every Chattahoochee Munitions 308 barrel
Cartridge and chamber dimensions follow the ANSI/SAAMI centerfire rifle standard.
Choose the CM7S for hunting, precision and suppressed subsonic shooting, or the CM10 for semi-automatic 308 with fast follow-up shots. New to the cartridge? Start with What Is 308 Winchester?, 308 Winchester subsonic or 308 bolt action vs semi auto.
CM7S Bolt Action Rifle, SBRs, and Pistols
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CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Bolt Action Rifle 16″ – FDE Metallic Cerakote
$2,649.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Bolt Action Pistol or SBR 12.5″ – FDE Metallic Cerakote
Price range: $2,649.00 through $2,749.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Compact Hunting Rifle 12.5″ SBR – WOOX Walnut Furniture
$2,749.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Hunting Rifle 16″ – WOOX Walnut Furniture
$2,749.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Overwatch Rifle 16″ – Cobalt Kinetics Green Cerakote
$2,649.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Suppressor Ready Rifle 16″ – Black Tungsten Cerakote
$2,649.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Bolt Action SBR or Pistol 12.5″ – Cobalt Kinetics Green Cerakote
Price range: $2,649.00 through $2,749.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM7S 308 Bolt Action Rifles, SBRs and Pistols
CM7S 308 Subsonic Bolt Action 12.5″ SBR or Pistol – Black Tungsten Cerakote
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CM7S Barreled Actions
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Approximate Lead Time is 3-4 WeeksBarreled Actions
CM7S 308 Barreled Action 16″ 1:8 Twist – Rem 700 Short Action
$1,768.98 Add to cart -
Approximate Lead Time is 3-4 WeeksBarreled Actions
CM7S 308 Subsonic Barreled Action 12.5″ 1:5 Twist – Rem 700 Short Action
$1,718.98 Add to cart
CM10 Semi-Automatic Rifles, SBRs, and Pistols
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CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 AR10 SBR or Pistol 12.5″ – Cobalt Kinetics Green Cerakote
Price range: $2,368.00 through $2,558.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 AR10 Firearms
CM10 308 Compact AR10 12.5″ SBR or Pistol – Black Tungsten Cerakote
Price range: $2,368.00 through $2,558.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 AR10 Firearms
CM10 308 AR10 Pistol or SBR 12.5″ – FDE Metallic Cerakote
Price range: $2,368.00 through $2,558.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 Battle Rifle 16″ AR10 – Black Tungsten Cerakote
Price range: $2,188.00 through $2,278.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 AR10 Rifle 16″ – Cobalt Kinetics Green Cerakote
Price range: $2,188.00 through $2,278.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 Semi Auto Rifle 16″ AR10 – FDE Metallic Cerakote
Price range: $2,188.00 through $2,278.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 Hunting AR10 18″ – FDE Metallic Cerakote
Price range: $2,068.00 through $2,158.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 Long Range AR10 18″ – Black Tungsten Cerakote
Price range: $2,068.00 through $2,158.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10 308 DMR Rifle 18″ AR10 – Cobalt Kinetics Green Cerakote
Price range: $2,068.00 through $2,158.00 Select options This product has multiple variants. The options may be chosen on the product page -
CM10 308 AR10 Rifles, SBRs and Pistols
CM10-SD 308 Subsonic AR10 12.5″ SBR or Pistol – Color Selectable Cerakote
Price range: $2,468.00 through $2,668.00 Select options This product has multiple variants. The options may be chosen on the product page
Magazines
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Magazines
CM10 308 AR10 Magazine – 20-Round Magpul PMAG LR/SR
Price range: $25.95 through $38.95 Select options This product has multiple variants. The options may be chosen on the product page -
Magazines
CM10 308 10 Round Magazine – Magpul PMAG LR/SR
Price range: $28.80 through $38.80 Select options This product has multiple variants. The options may be chosen on the product page -
Magazines
CM7S 308 Bolt Action Magazine – 10-Round Magpul PMAG AICS
Price range: $36.99 through $46.99 Select options This product has multiple variants. The options may be chosen on the product page
CM Ammunition
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Ammo
CM 308 Subsonic Ammo – 300 gr Maker REX Expanding – 20 Rounds
$57.99Out of stock. Join the waitlist to be notified when this product becomes available.
Choosing a 308 Winchester Rifle From District 308
The 308 Winchester combines useful terminal performance, wide ammunition availability and a case that fits both bolt-action and semi-automatic platforms. District 308 organizes every Chattahoochee Munitions 308 Winchester rifle as a complete system, because a rifle designed for conventional supersonic ammunition needs a different barrel twist, gas setup and suppressor than one designed around a 300 gr subsonic load.
CM7S 308 Winchester Bolt Action
The CM7S is a Remington 700 footprint short action with a three-lug bolt and a 60-degree bolt throw, an M16-style extractor, a pinned 20 MOA rail, an integrated recoil lug and a TriggerTech Remington 700 Primary trigger. Its barrels are Mos-Tek 416R stainless with 5R rifling and E100 Blackout Cerakote.
- 16-inch, 1:8 twist: the supersonic CM7S for hunting and precision with conventional 308 Winchester of 147 gr and heavier. See the 308 bolt action rifle, 308 suppressor ready rifle, 308 overwatch rifle and the walnut-stocked 308 hunting rifle.
- 12.5-inch, 1:5 twist: the subsonic CM7S, designed around CM’s 300 gr load; it can also fire heavy supersonic loads. See the 308 subsonic bolt action, 308 bolt action SBR, 308 bolt action pistol and the walnut-stocked 308 compact hunting rifle.
- Barreled actions: the 16-inch 1:8 308 barreled action and the 12.5-inch 1:5 308 subsonic barreled action for a Remington 700 short-action chassis or stock.
Because the action is operated by hand, it does not depend on propellant gas, so suppressor back pressure has no effect on how it cycles. Chattahoochee Munitions recommends an enclosed suppressor on every CM7S.
CM10 308 Winchester AR10
The CM10 brings 308 Winchester to CM’s large-frame semi-automatic platform with billet receivers, ambidextrous controls, an adjustable gas block, an adjustable AR10 buffer and a TriggerTech AR Duty trigger. The 12.5, 16 and 18-inch CM10 use 1:10 twist barrels for supersonic 308 Winchester and appropriate 7.62×51 NATO ammunition. CM uses rifle-length gas on its 16 and 18-inch CM10 barrels, which lets gas reach the action later in the pressure curve and gives a more manageable starting point for tuning, suppressed or not.
- 12.5-inch SBR or pistol: 308 AR10 SBR, 308 compact AR10, 308 AR10 pistol
- 16-inch rifle: 308 AR10 rifle, 308 battle rifle, 308 semi auto rifle
- 18-inch rifle: 308 DMR rifle, 308 long range AR10, 308 hunting AR10
For a supersonic CM10, Chattahoochee Munitions recommends a flow-through or low-back-pressure suppressor, which limits the extra gas pushed into the action and helps control receiver gas, extraction force and bolt speed. The reasoning is in the 308 suppressor guide.
The CM10-SD 308 Subsonic AR10
The CM10-SD 308 subsonic AR10 is not a conventional short-barreled AR10. It combines a 12.5-inch 1:5 twist barrel, CM’s 300 gr subsonic ammunition and an enclosed suppressor. A subsonic load produces far less gas than supersonic 308, so the CM10-SD needs the extra back pressure of an enclosed suppressor to cycle; a flow-through suppressor can release gas too freely. Do not fire supersonic ammunition through the CM10-SD. Read 308 Winchester subsonic and 308 twist rate.
Chattahoochee Munitions 300 gr 308 Subsonic Ammunition
Chattahoochee Munitions 308 subsonic ammo uses the 300 gr Maker REX, a CNC-machined, lead-free expanding bullet, loaded in new Starline 308 Winchester brass. From CM’s 12.5-inch 1:5 barrel it averages 1,005 fps with a 2.44 fps standard deviation over 10 rounds.
The load requires a 1:5 twist. Its 2.06-inch bullet is too long to stay stable at subsonic speed in a 1:8 or 1:10 barrel, and an unstable bullet can strike a suppressor baffle. Use it only in the 12.5-inch 1:5 CM7S and the CM10-SD. It is a close-range load: with a 100-yard zero it drops about 35 inches at 200 yards. See 308 ballistics.
308 Winchester and 7.62×51 NATO
Chattahoochee Munitions 308 Winchester firearms can use both 308 Winchester and appropriate 7.62×51 NATO ammunition. The two are closely related but are not defined by the same standards, so owners of other firearms should follow that maker’s markings and manual. See 308 Winchester vs 7.62 NATO.
308 Winchester Magazines
The CM7S and CM10 use different magazine patterns. The CM7S takes a short-action AICS-pattern magazine; the CM10 takes the dual-feed LR/SR pattern.
- 308 bolt action magazine for the CM7S
- 308 10 round magazine for the CM10
- 308 AR10 magazine, 20 rounds, for the CM10
308 Winchester Guides
- What Is 308 Winchester?
- 308 Winchester subsonic
- 308 twist rate
- 308 barrel length
- 308 ballistics
- 308 for hunting
- 308 bolt action vs semi auto
- 308 suppressor guide
- 308 Winchester vs 7.62 NATO
- 308 vs 6.5 Creedmoor
- 7mm-08 vs 308 (Variant Valley)
- 338 Federal vs 308 (Variant Valley)
- 308 vs 30-06
- 300 Blackout vs 308 (Sector 300)
- 8.6 Blackout vs 308 (Area 8.6)
- 6.5 Grendel vs 308 (Grendel’s Lair)
- 308 Winchester cartridge family (Variant Valley)
- What Is 243 Winchester?, the 308 necked to .243 inch (Predator Plains)
Browse by platform: CM7S 308 bolt actions, CM10 308 AR10 rifles and CM 308 subsonic ammunition.
308 Winchester Rifle FAQ
Who makes a 308 Winchester rifle?
Chattahoochee Munitions manufactures 308 Winchester rifles: the CM7S bolt action in 16-inch 1:8 and 12.5-inch 1:5 configurations with chassis or walnut furniture, CM7S barreled actions, the CM10 AR10 in 12.5, 16 and 18 inches, and the CM10-SD 12.5-inch subsonic AR10.
Who makes a 308 subsonic rifle?
Chattahoochee Munitions manufactures the 12.5-inch 1:5 twist CM7S bolt action and the CM10-SD subsonic AR10, both designed around its own 300 gr subsonic load.
Who makes 308 subsonic ammo?
Chattahoochee Munitions loads a 300 gr Maker REX in new Starline brass, averaging 1,005 fps from a 12.5-inch 1:5 barrel.
Is a bolt action or AR10 better for 308?
The CM7S bolt action suits hunting, precision and suppressed subsonic shooting. The CM10 suits semi-automatic use with fast follow-up shots. See 308 bolt action vs semi auto.
What twist rate does a 308 need?
1:10 handles common supersonic bullets; 1:8 stabilizes virtually the same ammunition from 147 gr up; and CM’s 300 gr subsonic load needs 1:5.
Will 308 subsonic cycle an AR10?
Not a standard AR10. The CM10-SD cycles CM’s 300 gr subsonic load with an enclosed suppressor attached.
What suppressor should I use on a 308?
Enclosed on every CM7S and on the CM10-SD; flow-through on a CM10 firing supersonic ammunition.
Can Chattahoochee Munitions 308 rifles fire 7.62×51 NATO?
Yes. CM 308 Winchester firearms can use both 308 Winchester and appropriate 7.62×51 NATO ammunition.
What magazines do CM 308 rifles use?
The CM7S uses short-action AICS-pattern magazines and the CM10 uses LR/SR-pattern magazines. They are not interchangeable.