The Alcan Max Fire primer was probably the hottest primer on the market at the time it was made, but the Federal primer could have been its equal. If you can find a copy of Lyman's first edition of their shotshell loading manual, you will find some data with this primer. Most of the data is for their powders, but there are other recipies. Do your best to try to find good data. I've seen or heard nothing about Vihtavouri primers.