This .450 Bushmaster, 5-round magazine is made using a .020 gauge, 410 stainless steel alloy and heat treated for durability. The magazine is then chemically treated for corrosion resistance and coated with a Marlube finish which burnishes into the surface to provide self-lubricating properties. It includes chrome silicon springs and an enhanced anti-tilt black polymer follower. Interior dimensions of OAL 2.316" +/- .002 are perfect for new ammunition and reloads. Made in the USA. Product Specifications Manufacturer: Ruger Model: AR-556 Caliber: 450 Bushmaster Capacity: 5 Rounds