Ruger® AR-556® MPR 450 Bushmaster Proper Magazine Alignment Tech Tip
This guide details a critical technique for the Ruger AR-556 MPR chambered in .450 Bushmaster, focusing on proper magazine loading to prevent feeding malfunctions. Instruction from a Ruger official highlights how incorrect loading can cause the cartridge rim to snag on the bolt catch. By ensuring a small gap (approx. penny thickness) between the top round's rim and the magazine's rear wall, users can achieve reliable chambering and smooth operation.












