The difference between the .277 and .284 is so slight, when I decided on one caliber for everything, I went with the 7mm. Back then, the bullet selection for .270 was pretty slim. If I had to make the choice today, I'd probably go with .270. I was looking for the highest SD and BC I could get at a weight I could stand to shoot. 7mm fills that pretty well. I shoot Berger 168 gr VLD in my WSM. It makes it a single shot rifle, but that is all you need if you do it right. When hunting bear, I fill the mag with 160 gr. Barnes, and they shoot close to the same point of impact. So far I haven't used the Barnes. The other issue with those long bullets is that I have to remove the bolt to empty the chamber. A PITA, but worth it for the groups thoes Bergers shoot.