I could not return a PM due to the fact that the system said it was blocked for some reason... strange...
so here is the gist of it, minus user's name...
Hey Dan I was wondering, you shoot a ton of .243 winchester, and I like to shoot it as well, I want to know have you ever tried Magnum primers with this powder and 100 grain bullets?
I haven't, but that combo should work very well. Winchester is using about 46 grains of the 780 behind their 100's... and a magnum primer would likely work great in that combo.