Do you have a chrono? It helps you get stats on a load you don't see on target. Let me clarify that statement. When I work up an accurate load with any powder in one of my 44 mags I get a velocity read with extreme spread and standard deviation. What I have been able to do is usually lower the numbers by switching primers or at least see if I am already using the best one. I have never had a problem with CCI mags as far as reliability or ignition. Although sometimes another brand of primers tweaks the load. I have found velocity variations such as CCI standard primers give me a certain velocity[1200 fps], switching to WLP the velocity seems to increase approx. +30 fps, and going with CCI Mag normally adds approx. +70 fps. According to my chrono there is also a velocity difference between the different types of mag primers. If I am going for top speeds CCI Mags almost always produced the top velocity.