CMMG: Caliber Profile: .458 SOCOM

Comparison of 5.56 and .458 SOCOM Rounds
Comparison of 5.56 and .458 SOCOM Rounds

Fayette, MO -( As legend has it, the concept for .458 SOCOM was invented over burgers and beer by members of the Special Forces community.

The discussion arose from recollections of Task Force Ranger’s experiences in which it took multiple shots – using 5.56 NATO – to bring down members of the opposing forces. Out of this, the inspiration for a caliber capable of delivering more energy at close distances was born.

A set of initial requirements were set forth that helped shape the design of the .458 SOCOM:

  • The cartridge had to fit in an M4 Carbine Platform with a proper barrel.
  • The cartridge had to fit in standard 5.56mm magazines.
  • It needed to be capable of firing at subsonic levels using suppressors.

As a result, Marty ter Weeme of Teppo Jutsu invented the .458 SOCOM cartridge in 2000. Tony Rumore of Tromix built and fired the very first .458 SOCOM rifle in February of 2001.

Upon testing, it was found that the .458 SOCOM not only lived up to the initial functionality requirements set forth, but also demonstrated the intended ballistics to make it a viable caliber for big game hunting.

With lighter bullets in the 140-400 grain range, the .458 SOCOM achieves velocities of 1600-3000 feet per second, which have proven to be extremely accurate out to 150-200 yards. When using heavier bullets between 500-600 grains, velocities will be approximately 980-1300 feet per second, which are ideal for suppressors.

While many wildcat calibers have been adapted to the popular AR15 platform over the years, concerns with longevity, durability and reliability have always plagued the AR15 platform. Many wildcat rounds require a significant removal of bolt material to accommodate the larger base of wildcat rounds. Removing material weakens the bolt and increases the chance of catastrophic failure when used with high performance wildcat rounds. While function is possible, the AR15 platform doesn’t provide much in terms of margin of error.

Thankfully, CMMG’s MkW ANVIL solves the issue by offering the durability of an AR10-sized bolt face to stand up to this potent caliber, throughout the wide range of bullet weights and muzzle velocities currently available on the market today. The CMMG MkW ANVIL was developed to be the new standard for rounds with case diameters exceeding the dimensions of the 5.56x45mm cartridge.

There are currently several prominent manufacturers of .458 SOCOM ammunition, including (but not limited to) the following:

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 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.

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