MDT Metal Magazines for Defiance XM Actions only. MDT Metal Magazines for XM actions are manufactured from high strength steel and finished with Cerakote Elite for the ultimate in durability and corrosion resistance. These magazines are available in both Standard (designed for use with 6.5×55 Swede) and Magnum (designed for use with 300 WSM family or 6.5 PRC) caliber options, with a 10 round capacity for Magnum and a 10 round capacity for Standard.