When a cartridge case is necked-down it becomes less efficient and less powerful. And, of course when a case is necked-up it becomes more efficient and potentially more powerful. That's why a .25-06 is less efficient (for amount of powder used) and less powerful than its parent case, the .30-06, and why the .35 Whelen is more efficient and powerful than its parent the .30-06. The most efficient and powerful cartridges, potentially, are straight wall, assuming suitable powders and projectiles.
The .416 Ruger would be more efficient and powerful if made into a .458 (I'm sure it's been done), and why it's more efficient and powerful than the .375 Ruger. If I were serious about a .416 it would likely be the .416 Taylor because of its efficiency (using far less powder) to get 2400 from a 400gr.
But 94 grs powder for about 2640 fps from a 350gr TSX in .416 doesn't compare well with 2780 fps from a 350 TSX using 81 grs powder in my 24" Ruger #1 in .458 - which is a straight-wall cartridge. Of course, I know the 350 in .416 has a better SD and BC, so better at longer ranges, but it still has 21% less cross-sectional area than .458-cal.
Bob
www.bigbores.ca
