The SOCOM is an awesome cartridge that is basically a long 50AE (O.A.L. of 1.575″) with a rebated .308 style head configuration, necked down to utilize a .458″ diameter projectiles. It has been chambered in some bolt guns but its claim to fame is in the AR-15 platform.  This case is designed for use in correct US manufactured .458 SOCOM firearms, dies, and ammunition; not the improper dimensions provided in the CIP cartridge/chamber print.

**Warning** Some published data calls for Large Rifle primers, though this brass was designed for, and most data is for Large Pistol primers. If you are to use the taller Large Rifle primer, Starline recommend reaming the primer pocket deeper (.125”-.132”). Seating the Large Rifle primers in a standard Large Pistol pocket may cause high primers, which could cause slam-fire issues and chambering issues in general.

In firearms that use a floating firing pin (such as the AR-15 and its variants), dropping the bolt on a chambered round could lead to a slam fire. It is important that these firearms are loaded from the magazine so that the bolt loses inertia when it strips a round from the magazine. It is also important NOT to use sensitive primers that aren’t designed for use in an AR, as this increases the chance of a slam fire.