I read a test a member of another forum did with regular and magnum pistol primers. I can't find it right now, but I'll post it when I do. He compared Remington, Winchester, CCI and Federal SPP in standard and magnum. No pressure testing, just velocity. The posted results were for 38 special, but IIRC he had done almost as thorough of a test with 9mm as well. He did light target loads as well as loads that bordered on max. It was interesting. There was very little difference was the main result. One thing that did stand out to me was CCI Magnum performed almost identical to Federal Standard in each test he did. This was noticeable mainly because I only use Federal primers since some of my revolvers have very light actions and will not fire with CCI. Since the last shortage, I have used Federal Magnum in SPP and LPP exclusively since that was all I could find at the time. I did my own testing that was not nearly as thorough as the one I read, but what I found is with very light loads with Bullseye in 38 special, there is very little difference in velocity. There was more variance from gun to gun with equal loads than there was was by changing primers. Accuracy was equal as well. I also did a little test comparing magnum SPP to standard small rifle. I did notice a slight increase in velocity. Not a lot, but enough to notice, but even with close to max loads, the rifle primers never showed any sign of high pressure. I saw no sense in pushing the envelope with hot loads, because all I was concerned about was the load I would be shooting day to day. I know its not recommended, but I'll continue to use Magnum primers in all of my handguns large and small because I have a good inventory. If that runs out, I guess I will use what I can find.