The CMMG MkW-15 Anvil Rifle chambered for the .458 SOCOM cartridge (or 6.5 Grendel) is one of the many modifications and versions of the AR platform that have been developed as a result of its huge and unmatched popularity. With the U.S. military in mind, the .458 SOCOM was created to provide them with greater power than other common calibers. The 5.56 AR magazines can accommodate the .458 SOCOM, which is obviously a huge convenience given how inexpensive and widely available 5.56 magazines are. CMMG designed the Anvil from the .308 AR-10 rather than the AR-15 since the .458 SOCOM is a heavier and hotter cartridge than the 5.56. The heavier .458 round can be supported by the AR-10 more effectively than the lighter AR-15 because of its far stronger and more resilient bolt carrier group. CMMG offered the Anvil in three different configurations: T (equipped with mil-spec furniture and trigger), XBE (equipped with a mil-spec trigger with 6-position stock and Magpul MOE grip), and XBE2 (equipped with an SSA 2-stage trigger with Magpul MOE furniture). There are also the Banshee, Resolute, and Endeavor MkW models available. The main difference between shooting the CMMG MkW-15 and shooting any other AR-10 rifle is that the CMMG will give you more kick thanks to the heavier .458 SOCOM round.