Re: CCI BR-4
Sometimes a primer will not seat flush.
When primers are manufactured, the anvil feet protrude a small distance, and when the primers are seated these feet get pushed flush with the primer rim, and this preloads the primer compound capsule, sensitizing it, or essentially 'arming' the primer.
If the primer cup itself is not seated deeply enough, sometimes this condition results in a primer that is not properly 'armed'. When the firing pin strikes it, this usually completes the seating process, but often also absorbs so much of the firing pin's energy that it fails to discharge the primer.
Outwardly, the primer looks good, and the shooter often concludes they either had a faulty primer or a light primer strike. Usually, if the primer seating depth was the actual issue, the primer will ignite with a second strike.
There may not be anything wrong with your primers. Make certain your primers are seated flush.
Greg