In my opinion, since a hunt is a living, breathing, organic and dynamic thing, there can be no excess in your pursuit of accuracy. a little mirage, 50 yards of error in range estimate, a bit of fatigue, and too long in between practice sessions will be enough to send your shot 3-4 inches out of the kill zone. A person with a 1.5 moa rifle can count on accuracy on a 4.5 inch target at 300 yards. If you change that to a 2.5 moa rifle, an average shooter will be really stretching his abilities to hit an 8 inch circle at 300.
Since these hunts are, as I said, dynamic, what happens when several other factors add in their effects? A bit of wind, a slight downhill tilt, a bit of a twitch? add 4 more inches, and you will have either missed your shot, or wounded an animal.
I think a person who takes anything less than a 1.5 MOA rifle into hunts that will provide 300 yard shots is wrong. Same thing stands for one who chooses a non magnum velocity round for 300 round or farther hunts.
shooting is all about chaos. It is your challenge to overcome that chaos. shooting paper over iron sights in one handed rapid fire matches is one thing; aiming at an elk with a worn out 30-30 two hills over is a crime.
You need an accurate package, though, not just a rifle that can shoot peas off of a fork. a 1.5 moa rifle, a great clear scope, and top quality ammunition are enough for someone who is up to the challenges of 300 yard shooting.
I guess my problem is that I really abhor misses and wounded game. A lot of people don't give a darn if a deer gets away, but myself, if I shoot, I want it dead, there, now, not three days later and eaten by buzzards.
I also feel very badly about anyone who chooses to use really marginal cartridges for hunting. There is no such thing as overkill, it is a nonsense term. Underkill is simple, it means NOT DEAD. If you shoot something, do it accurately, and with an adequate cartridge, so that if you shoot something, you don't underkill it.