Sab, I'm surprised nobody mentioned it, but you can sometimes experience excess pressures with loads that are too light. This usually happens with powders such as Bullseye. There are many explanations, but I'm not sure anybody knows exactly why. You shouldn't have to go with a Small Pistol Primer as opposed to a Magnum if the load in question calls for a Magnum. Of course if it doesn't...Personally, I'd stay with the exact primer specified if I was having trouble.
Glad to hear you got a load that would work.
