The .280 is a stretched 7x57, invented for American who have a .270 phobia yet somehow can't bring themselves to hunt with a German round. This mental aberration was first exhibited by the British, who for similar reasons felt compelled to rename the 7x57 the .275 Rigby.

The .280 Ackley Improved, on the other hand, is a broad-shouldered, manly round, developed for rifle loonies who have 7mm Remington Magnum phobias.

A little-known fact is that a great many of our present hunting cartridges were invented by psychiatrists who decided to cash in on the irrational fears of many shooters who aren't just rifle loonies, but certifiable rifle loonies.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck