A:
All of those are 30 caliber rounds, just different variations of it. Note, they are DIFFERENT ROUNDS. The most common is the .300 win mag. It's one of the most efficient rounds availible. I do not recommend the short mag in any caliber. If you look at ballistic charts, their performance just really isn't that much better, if any, to justify the difference in price for the ammo. My personal favorite caliber is .270. I shoot hornady SST's in 140 grain and get deadly accuracy and lots of knock down power.