i have noticed a pattern with most all of the load data i'm gathering (.357 magnum), and that is, for loads using imr-4227, recipes using magnum primers are using a little less powder. i have both standard and magnum primers, and i'll try both, no doubt, but, are there any advantages to one over the other? i use the imr-4227 a lot for .44 magnum, but never with magnum primers. are the magnum primers better for cold weather? i live in an area where i could be shooting in below zero weather in winter, 100 in summer.