CMMG’s GUARD Withstands the Mighty 450 SMC

CMMG's GUARD Withstands the Mighty 450 SMC
CMMG's GUARD Withstands the Mighty 450 SMC

Boonville, MO-(Ammoland.com)- CMMG's MkG GUARD is an AR15 rifle that is chambered in .45 ACP and feeds from factory Glock magazines. At the heart of the GUARD is the patent pending Radial Delayed Blowback operating system that works to harness the strong recoil impulse of .45 ACP. After extensive durability testing, CMMG is proud to announce that the GUARD is safely rated for 450 SMC.

For those unfamiliar with 450 SMC, Triton first conceived the cartridge in 2001. The design was ultimately taken over and completed by DoubleTap ammunition years later. In essence, it is a magnum version of .45 ACP that offers ballistics that are comparable to 10mm. It is a true “stopper” that delivers energy capable of taking down big game.

In essence, the 450 SMC is a magnum version of .45 ACP that offers ballistics that are comparable to 10mm.
In essence, the 450 SMC is a magnum version of .45 ACP that offers ballistics that are comparable to 10mm.

While the 450 SMC uses a case with the same outer dimensions as .45 ACP, there are a few significant differences that allow DoubleTap to load 450 SMC with five to six thousand pounds per square inch of pressure more than a standard .45ACP. First, the 450 SMC uses a small magnum rifle primer instead of the large pistol primer. This modification allows the hardened case to be thicker at the base. Second, the brass is manufactured from the ground up to handle up to 30,000 pounds of pressure. The result is a dual-purpose cartridge that is exceptional for both hunting and personal defense.

While 450 SMC can be safely run in any .45 ACP that is rated for +P ammunition, the amount of rearward force created by such a hot load would potentially be problematic from a straight blowback AR15. CMMG's GUARD platform can overcome these issues, however, thanks to the Radial Delayed Blowback operating system.

While 450 SMC can be safely run in any .45 ACP that is rated for +P ammunition, the amount of rearward force created by such a hot load would potentially be problematic from a straight blowback AR15.
While 450 SMC can be safely run in any .45 ACP that is rated for +P ammunition, the amount of rearward force created by such a hot load would potentially be problematic from a straight blowback AR15.

The Radial Delayed Blowback system uses up some of the recoil impulse of the spent round to unlock the rotating bolt from the barrel extension. This mitigates the leftover rearward force that then drives the carrier back to cycle the action. By eliminating some of this rearward force during the unlocking sequence, the GUARD requires less weight in the bolt carrier group and buffer to safely cycle. This reduction in reciprocating mass results in less felt recoil for the end user.

Here's how the 450 SMC stacks up against 10mm out of a 16-inch barrel (data provided by DoubleTap Ammunition):

450 SMC vs. 10mm Auto
450 SMC vs. 10mm Auto

CMMG Lifetime Quality Guarantee

CMMG, Inc. will guarantee its products against defects in material or workmanship. CMMG, Inc. will repair, replace or substitute part(s) (at CMMG, Inc. discretion) at no charge to the customer if a defect of material or workmanship is found. All service work must be carried out by CMMG, Inc. The warranty applies to the original purchaser and a copy of the invoice or proof of purchase must be provided when submitting for service or work.


About CMMG:CMMG

CMMG began in central Missouri in 2002 and quickly developed into a full-time business because of its group of knowledgeable and passionate firearms enthusiasts committed to quality and service. Its reputation was built on attention to detail, cutting edge innovation and the superior craftsmanship that comes from sourcing all their own parts. By offering high quality AR rifles, parts and accessories, CMMG's commitment to top-quality products and professional service is as deep today as it was when it began.

  • 6 thoughts on “CMMG’s GUARD Withstands the Mighty 450 SMC

    1. I agree with what you said. Now, if they made it in a S&W 460 like my 460V. That would be a ton of fun. Would make shooting a 300+ grain 460 manageable. I know after 30 rounds in the 5″ model I have it feels punishing. Having a 460 [email protected] AR would be an interesting new market.

    2. What are the part numbers to use with the Guard and the cost? is it the same one that is to be used with a suppressor?

      1. I agree with what you said. Now, if they made it in a S&W 460 like my 460V. That would be a ton of fun. Would make shooting a 300+ grain 460 manageable. I know after 30 rounds in the 5″ model I have it feels punishing. Having a 460 [email protected] AR would be an interesting new market.

      2. @Jason,

        No, it is not frivolous at all, if you take the time to think about it.

        This chambering allows the owner to run both 450 SMC and 45 ACP; the latter for target practice, and the former for actual self-defense carry and or hunting.

        Their choice of 450 SMC allows a wider customer base right out of the shoot, because of the applicability of using 45 ACP, of which tens of millions of people already shoot through their 1911’s, and other 45acp platforms.

        Cmmg made a smart move by this chambering, they designed a product that already has tens of millions of potential customers waiting for the product.

        Like I said, take the time to think about this and both marketing terms, and sales terms, within the sphere of real-world ownership and use, of the 45 ACP round.

        1. @james
          The rowland kit i have does just that with a mag change. One good thing i guess is that i have another calibre to shoot in my rowland.

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