Speed kills, and a good bullet is more efficient at it. They are my bolt action bullets of choice, but don't take my word for it. Maybe a legend can convince you. Cheers
Jack O'Connor extolled the virtues of the 270Win for all sorts of good reasons, but mostly because he got "paid" to do so, until he found out he had a dedicated audience who also appreciated the excellent cartridge.
However, O'Connor also extolled cartridges such as the venerable 30-06 Springfield and even the 30-30Win.
O'Connor made a lot of money and gained a lot of valuable notoriety, along with his wife Eleanor, on the back of the 270Win.
That wouldn't have been possible if the cartridge wasn't as good as it was and still is.
I remember him making a comment at a trade show, comparing the Swede 6.5x55 to the 270Win. He called them "somewhat twins" when loaded with comparable bullet weights to equal velocities. There was a lot more, but that's the part which stuck with me and started my love affair with the 6.5x55 Swede as well.
Up until a decade ago, I've always avoided the 270Win, or any other 270 cal cartridge. NOT BECAUSE THERE WAS ANYTHING WRONG WITH THEM.
I shoot a lot of different cartridges and calibers, especially which share bullet diameters, such as 223, 243, 25, 264, 284, 308-312, 323, 338, 458.
That covers a huge spectrum of performance, none of which the 277 cal cartridges do better or worse, and really do nothing else but fill a very small gap between some already very capable cartridges.
For a long time, other than a few wildcats, there really weren't any other cartridges utilizing the 277 diameter bullets than the 270Win.
I didn't need or want another "odd" caliber on the shelf, which couldn't be used in any other cartridge, or that I felt like going down another rabbit hole with a wildcat.
I had friends doing that, they made up 277/308 chambered cartridges, 277x39 improved cartridges, 277x57, and one even had to try his hand at his own magnum cased 277, based on the 458 Win mag, because he had a lot of cases on hand and a 277 barrel he had picked up somewhere.
They were all fun and interesting, but ??????????