One of the best features of the 300 mags is they cut down on wondering. Wondering costs a lot of money and time; especially if it leads you to want to bridge the gap between wondering and knowing. Wondering if your .300 is a good choice for a (insert name of thin skinned game here) at (insert any range you are proficient at) in (name a condition) is largely a waste of time because inevitably the answer is "yes." If you're wondering if something else is much better in a more specific situation the answer is "Maybe but not by much".
This should clear your mind for wondering something that matters like where your next trip should be.