General Exclusive on the Colt Modular Carbine (CMC) CM901 Multi-Caliber Rifle

Close-up of AR-15 rifle and magazines with ammo

Much noise has been made over the past few years about the integration of a multi-caliber AR-style platform to the U.S. armed forces.

The FN SCAR (in 5.56 NATO and 7.62 NATO) and the Bushmaster ACR (in 5.56 NATO and 6.8 SPC) have both been tossed around as multi-caliber replacements for the M4/M16 currently in use.

Now Colt has introduced its solution with the CM901 Colt Modular Carbine.

“Modular” and “multi-caliber” are actually understatements, since the CM901 is, hands, down, the most versatile battle rifle/assault rifle we’ve ever seen in both respects.

The heart of this versatility lies in the combination of the patent-pending AR (AR-10/AR-15)-format “universal” multi-caliber lower receiver and conversion system and Colt Defense’s various AR operating systems and uppers, which lets you configure the gun in so many mission-specific ways. It’s almost mind-boggling.

The CM901 provides a truly sumptuous feast of versatility with regard to configuration options.

Select-Fire AR

The Colt CM901 Modular Carbine is a select-fire AR (AR-10/AR-15)-platform weapon, so it immediately looks, feels, handles and shoots in a way that’s immediately familiar to all military end-users, including general infantry personnel. It also benefits from the AR platform’s now legendary ergonomics/usernomics.

Configurable in Many Calibers

The CM901 multi-caliber battle carbine can be configured in any/every caliber between 7.62×51mm NATO (7.62mm NATO)/.308 Win. and 5.56×45mm NATO (5.56mm NATO)/.223 Rem., including 6.8 SPC (6.8×43mm SPC) and 6.5 Grendel, depending on what U.S. military end-users require.

To switch from 7.62mm to 5.56mm:

  1. Push out the two receiver pins.
  2. Take off the 7.62×51mm upper module
  3. Slap the 5.56mm upper module on.
  4. Push the two receiver pins back in
  5. You’re good to go.

Accepts Legacy Milspec 5.56mm Upper Receivers

The CM901 universal lower receiver accepts any/all legacy MILSPEC 5.56mm NATO AR rifle/carbine/SBR upper receivers already in the U.S. military inventory, including the:

  • Colt M4/M4A1 Carbine 14.5″ AR carbine
  • M4 Commando 11.5″ AR SBR
  • MK18/CQBR (Close Quarters Battle Receiver) 10.3″ AR SBR
  • M16A3/A4 20″ DGI rifle uppers.

The CM901 lower also accepts the…

  • Colt LE6940 16″ monolithic upper
  • Colt LE6920 16″ M4/M4A1 Carbine-type uppers.

Thus, 5.56mm barrel length is determined by whatever AR upper you want to use.

And later:

Fully Ambidextrous Controls

The CM901 sports fully ambidextrous controls a.k.a. “full ambi controls” including…

  • Ambidextrous safety/selector switch
  • Bolt catch hold-open/release lever
  • Magazine release button

The MagPul 20LR 7.62 Magazine

The CM901, when configured for .308 Win, uses the MagPul 20LR 7.62 magazine. The weapon also accepts the SR25/M100 7.62mm magazine. The weapon, when configured for 5.56mm, accepts all MIL-SPEC 5.56mm magazines.

What are your thoughts on the Colt CM901? Share your thoughts in the comment section.

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Comments (4)

  1. A lot could be achieved by simply going to a, say, 7.62NATO, & using a variant of the ‘.30-’06/.223 Accellerator’ ctg (a 30-06 sabot carrying a 223), & put whatever bullet in…better would be a straight-neck wildcat of the 762 that would have a .458 (I guess) sabot carrying whatever bullet, & an adj gas-system; this would allow a big ‘ol subsonic-sniping ctg for close range, esp w/ a gas-shut-off for quiet, manual recycling the action (DeLysle carbine)

  2. Famous AR ergonomics? You have to be kidding. The use of ergonomics and the AR (or M-xx anything) are a joke. The AK may be slightly worse, but only slightly.

    Try one of the new carbines/rifles like the XCR, SCAR-L, ACR or even the FAL if you want to get well done controls.

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