CMMG MkW-15 AR-15 458 SOCOM 10-Round Polymer Magazine - Black

The CMMG MkW-15 AR-15 458 SOCOM 10-round polymer magazine is purpose-built for shooters running the big-bore .458 SOCOM cartridge in their modern rifle platform. Based on the proven Lancer L5 Advanced Warfighter design, CMMG engineered these magazines with modified feed lips that reliably cycle .458 SOCOM ammunition without compromising the integrity of the hardened steel lips. This isn't a generic magazine with a band-aid fix — it's a refined execution of a magazine that handles the unique demands of subsonic and supersonic 458 SOCOM rounds reliably.

Built from impact-resistant polymer with a slim profile, the MkW-15 delivers the durability and weight savings you need in the field while maintaining steel feed lips and a stainless steel spring where it counts. The constant-curve internal geometry and non-tilt follower keep rounds feeding predictably, and the aggressive texturing on the body gives you confidence gripping the mag during tactical reloads. The slide-on floor plate makes disassembly simple for cleaning or repair, and the whole package is designed, tooled, manufactured, and assembled in the USA.

Fair warning: this magazine is a modified 30-round 5.56 magazine, so it will still hold 30 rounds of standard rifle ammo if needed — useful for backup or transition shooting. For .458 SOCOM, the design is optimized for 10 rounds, though it can physically accommodate 11 if forced. The magazine is laser-engraved with the caliber marking so you'll never confuse it in your kit. Check your local and state magazine laws before ordering; we cannot ship to Hawaii, Maryland, Massachusetts, New Jersey, New York, California, Connecticut, Colorado, Washington D.C., Chicago, Aurora, Oak Park, Illinois, or South Bend, Indiana.

Key Features

• Modified Lancer L5-AWM platform optimized for .458 SOCOM ammunition
• Hardened steel feed lips — no machining, no weakness
• Impact-resistant polymer body with aggressive grip texturing
• Non-tilt follower and constant-curve internal geometry for reliable feeding
• Stainless steel spring for corrosion resistance and longevity
• 10-round capacity designed for .458 SOCOM; also feeds 5.56 NATO if needed
• Slide-on floor plate for easy field disassembly and cleaning
• Laser-engraved caliber marking
• USA designed, manufactured, and assembled

Specifications

Frequently Asked Questions

Will this 458 SOCOM magazine work in an AR-15 platform?

Yes — this is an AR-15 pattern magazine. It's designed specifically for .458 SOCOM cartridges and will feed them reliably through your 458 SOCOM upper receiver.

Can I use this magazine for 5.56 NATO ammo?

Yes. This magazine is a modified 30-round 5.56 magazine, so it will feed standard 5.56 NATO ammunition. However, it's optimized for 10 rounds of .458 SOCOM, which is the typical application.

How is the CMMG magazine different from a stock Lancer L5-AWM?

CMMG modified the feed lips to reliably handle the wide range of .458 SOCOM ammunition on the market without machining or weakening the hardened steel feed lips. This engineering refinement solves the feeding inconsistencies some shooters experience with unmodified 5.56 magazines in 458 SOCOM rifles.

What states have magazine capacity restrictions?

We cannot ship this product to Hawaii, Maryland, Massachusetts, New Jersey, New York, California, Connecticut, Colorado, Washington D.C., Chicago, Aurora, Oak Park (Illinois), South Bend (Indiana), or other jurisdictions with magazine capacity laws. Please verify your local and state laws before ordering.