I know this has been covered before but I keep hearing people say i havent seen flat primers when referencing to cartridges like 44 spl and 45 colt. Im going to put this out there for all the fellers getting into reloading. THIS IS BAD ADVICE DO NOT USE PRIMERS AS A TOOL FOR MEASURING PRESSURE. as ya get a little experience you will see primers like win lrp flattening with higher pressure rounds up above 40000 cup and get flatter the higher ya go. The primer materials and thickness will also play a role in this . A lot of pistols will detonate long before ya get to this point period. So all im saying is please dont rely on primers to develop loads thats what pressure transducers are for