Mr. Ackley, along with about two dozen others, improved the .300 H&H case (often in the 1917 Enfield surplus action) to increase powder capacity and reduce "back thrust" on the bolt... Mr. Ackely's books, available from eabco.com, sinclair, ebay, etc. detail many of these experiments. After a decade or two of this post WW I experimenting, Mr. Weatherby decided to do the same thing, ONLY using a rounded "radius" shoulder/and neck junction. (.300 Weatherby) i). reportedly the radius causes turbulance that slows pressure build and permits higher overall powder charges, longer working... He also used alot of freebore. ii). reportedly, after his death, he said that rounded shoulders are harder to copy... ask any machinist.
You can fire Weatherby ammo in a properly done Ackley chamber, but the radius shoulder blows out and will no longer work well in the Weatherby chamber... Resizing is a pain.
.300 Win. is much newer. '60s as I recall. Same pressures, 55K CUP, but a case short enough to work in the standard .30/'06 length actions. Either will give you about all the preformance you can stand with reasonable barrel life. Next up is the .30/.378 Weatherby if you can stand the kick and low barrel life... luck
