I am new and am gearing up to reload. I already own a Mini-14 and have a Lee press and 223 dies, etc... I will be acquiring an M1 Garand in the near future. I wanted to know if there are any powders that can be used in both cartridges (30-06 and 223/556) to good effect? Or is this an...

What effect can different primer's have on a load? Presuming your using the correct size, do different brands of primers really make a difference with the same powder? (i.e Remmington, Winchester, or CCI's effect on Reloader #7) And can you tell the difference if you don't have a chronograph?