Did you chrono these ?Did some scientific testing comparing the CCI small rifle and small pistol magnum. Loaded up 10 rounds of same load only changing the primer in the 300bo. Accuracy was identical and there was no appreciable difference in velocity. Also the firing pin strike on both primers could not be distinguished. I am convinced they are either the same primers or close enough u can't tell them apart. Take those results for what you will or give it a try yourself.
Rosewood