CCI Ammunition - Primer Details
Mil-spec sensitivity
Initiator mix optimized for ball/spherical propellants
Available in large (No.34) and small (No. 41) rifle
Use the same data as CCI Magnum primers
The Number 41 primer is the same as the 450 magnum primer but the cup is thicker in the base requiring more force to set off the primer.
The vast majority of slam fires occur when when a single round is loaded without the magazine in the rifle to slow down bolt velocity and firing pin inertia.
Now the good news, when Remington ran Lake City the 5.56 ammo used the 7 1/2 primer that has a cup thickness of .025.