The Mil-Spec No. 41/5.56 primer provides the most reliable, consistent ignition. It's built to military specifications and specifically designed for use in 5.56 cartridges. Number 41 Mil-spec primers are made to the same specifications of the U.S. Military and reduce the chances of a slam-fire. While designed for you in Military-style semi-auto rifles, they use the same data as CCI magnum primers.
Specifications: Name: #41 Primers Part #: 0001 Caliber: 5.56mm Bullet Style: Small Rifle UPC: 076683500014 - 1000 ct. (10 Trays of 100) UPC: 076683000019 - 100 ct. (1 Tray of 100)
Note from CCI: Effective slam-fire prevention requires more than mil-spec primers. Headspace, chamber condition, firing pin shape and protrusion, bolt velocity, case condition and other factors can affect slam-fire potential.