Its completely normal. Most military semi-autos have free floating firing pins such as in the AR-15, M1 Garand, M14, SKS, etc.At least the first three on the list cannot fire out of battery so long as everything is in spec- the firing pin is held captive until the bolt locks and the inertia of the firing pin then moves forward and dimples the primer.

CCI makes milspec primers, personally I think they are overkill. I've shot thousands of handloads trough the M1 Garand with the 'soft' Federal 210 primers (yes they dimple every time) and I shoot remington 7 1/2s and winchester WSRs throught the AR15- never had one go off from the pin's inertia. Most important is that the primers get seated below flush to avoid slamfiring.