I'm new to precision rifles and honestly haven't even gotten my first one. I'm learning about certain rounds before I even have eyes on a rifle. I recently heard of the 7mm class and was wondering what is the difference between the 7mm Winchester short mag and the 7mm-08? Is it .223 vs 5.56 different or are there more differences then that? my only real rifle training is what the army gave me with the M4. Thank you for your time.

EDIT: The only thing rifle wise I am looking at bolt action. Because I know simi I well rush my shot and send rounds down range that will be unneeded and/or sloppy.