What Is 6mm Creedmoor? The Short-Action 6 mm Cartridge Explained

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What is 6mm Creedmoor? The 6mm Creedmoor, often shortened to 6 Creedmoor or 6 CM, is a .243-caliber, rimless, bottlenecked rifle cartridge made by necking the 6.5 Creedmoor case down to 6 mm. It began as a wildcat soon after the 6.5 Creedmoor appeared in 2007 and was standardized by SAAMI in 2017. It fires long, high-BC 95 to 115 gr bullets at about 2,950 to 3,100 fps with light recoil from a short action or an AR10. Chattahoochee Munitions manufactures the 6mm Creedmoor on its CM10 large-frame semi-automatic platform with an 18-inch CrMV barrel, 5R rifling and a 1:7.5 twist.

What Is 6mm Creedmoor at a Glance

Specification 6mm Creedmoor
Standardized SAAMI, 2017
Parent case 6.5 Creedmoor, necked down
Bullet diameter .243 inch
Case length 1.920 inches
Cartridge overall length (SAAMI) 2.800 inches
SAAMI pressure limit 62,000 psi
Common factory bullets 87 to 115 gr
Published velocity Hornady 108 gr ELD Match at 2,960 fps from a 24-inch test barrel
Chattahoochee Munitions twist 1:7.5 on the 18-inch CM10 6mm Creedmoor

Cartridge and chamber dimensions are published in the ANSI/SAAMI centerfire rifle standard.

Where the 6mm Creedmoor Came From

After Hornady introduced the 6.5 Creedmoor in 2007, precision shooters necked it down to 6 mm for less recoil and a flatter path with long, slippery bullets. The 6mm Creedmoor became a favorite in precision rifle competition, factory ammunition followed, and SAAMI standardized it in 2017. Compared with the older 243 Winchester, it has a sharper shoulder, a longer neck and room for long bullets without seating them into the powder space.

What Is 6mm Creedmoor Used For?

What is 6mm Creedmoor used for? Precision shooting at distance and medium-game hunting.

  • Deer and pronghorn: with a 95 to 103 gr expanding hunting bullet and good shot placement.
  • Coyotes and hogs: flat trajectory and enough bullet weight for hogs.
  • Steel and paper at distance: high-BC 105 to 115 gr bullets with light recoil, so you can see your hits.

Chattahoochee Munitions does not recommend the 6mm Creedmoor for elk or bear. For elk, choose 338 Federal or 375 Raptor; for bear, 458 SOCOM XL or 375 Raptor.

What Is 6mm Creedmoor Performance Like?

The 24-inch muzzle figure is Hornady’s published number. Downrange values and the 18-inch row are Chattahoochee Munitions calculations (published G7 BC 0.270, 200-yard zero, standard atmosphere, 10 mph full-value wind; 18-inch velocity estimated at 30 fps per inch below 24 inches). They are not chronograph data.

108 gr ELD Match Muzzle 300 yd 500 yd Drop at 500 yd Wind at 500 yd
24-inch (published muzzle) 2,960 fps / 2,101 ft-lb 2,446 fps / 1,435 ft-lb 2,133 fps / 1,091 ft-lb -38.1 in 15.9 in
18-inch CM10 (calculated) 2,780 fps / 1,853 ft-lb 2,284 fps / 1,251 ft-lb 1,984 fps / 944 ft-lb -43.9 in 17.5 in

What Is 6mm Creedmoor Twist Rate?

The CM10 6mm Creedmoor uses a 1:7.5 twist, fast enough for the long 105 to 115 gr bullets the cartridge is known for, and it also fires 87 to 103 gr hunting bullets. Factory 243 Winchester rifles often use 1:9.5 or 1:10, which is why many cannot stabilize the heaviest 6 mm bullets. Read 6mm Creedmoor vs 243 Winchester.

Is 6mm Creedmoor a Subsonic Cartridge?

No. Chattahoochee Munitions treats the 6mm Creedmoor as a supersonic cartridge, and the CM10 6mm Creedmoor is set up for supersonic ammunition with a flow-through suppressor rated for 6 mm. For subsonic shooting, look at 8.6 Blackout subsonic or 375 Raptor subsonic.

6mm Creedmoor Compared With Other Cartridges

6mm Creedmoor Rifles From Chattahoochee Munitions

The CM10 6mm Creedmoor uses an 18-inch chrome moly vanadium (CrMV) barrel with 5R rifling, a 1:7.5 twist, 5/8×24 muzzle threads and Tactical Grey Cerakote, rifle-length gas, a .750-inch Superlative Arms adjustable gas block, an Odin adjustable buffer, a TriggerTech Duty trigger and a B5 Systems SOPMOD stock. It weighs 7 lb 14 oz with an unloaded magazine and ships with one 10-round Magpul PMAG LR/SR magazine. Choose the 6mm Creedmoor AR10 in Black Tungsten, the 6mm Creedmoor rifle in Cobalt Kinetics Green Cerakote or the 6mm Creedmoor semi auto rifle in FDE Metallic, browse CM10 6mm Creedmoor AR10 rifles, or see the full Predator Plains lineup.

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What Is 6mm Creedmoor FAQ

Is 6mm Creedmoor the same as 6 Creedmoor?

Yes. “6 Creedmoor” is a common short name for the 6mm Creedmoor.

What is 6mm Creedmoor made from?

The 6.5 Creedmoor case necked down to .243 inch.

Is 6mm Creedmoor good for deer?

Yes, with a 95 to 103 gr expanding hunting bullet and careful shot placement.

Is 6mm Creedmoor good for elk?

Chattahoochee Munitions does not recommend it for elk. Choose 338 Federal or 375 Raptor.

What twist rate does 6mm Creedmoor need?

About 1:7.5 to 1:8 for 105 to 115 gr bullets. The CM10 6mm Creedmoor uses 1:7.5.

Will 6mm Creedmoor work in an AR10?

Yes. It fits AR10 (LR/SR) magazines. The CM10 6mm Creedmoor ships with a Magpul PMAG 10 LR/SR.

Who makes a 6mm Creedmoor AR10?

Chattahoochee Munitions manufactures the CM10 6mm Creedmoor AR10 with an 18-inch CrMV 1:7.5 barrel in Black Tungsten, Cobalt Kinetics Green and FDE Metallic Cerakote.

Who makes 6mm Creedmoor ammunition?

Hornady and several other makers load it. Chattahoochee Munitions does not load 6mm Creedmoor ammunition.

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