Defiance anTi XM length action, mag bolt face, right bolt right port, and integral recoil lug. Extended ejection port, swept bolt handle, mini M16 extractor, plunger ejector. 416 SS action body, 4340 chrome moly bolt, deep right spiral flutes, Remington style magwell with feed lips for hinged floorplates, Remington style rear tang, cut for XM box.