What kind of case capacities and performance differences are there between these two cartridges?

Apples to apples you will never catch the bee. That said you can get pretty close with a lot less powder. Check out this threads. It had a lot of good info.

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/2523237/page/0/fpart/1

To back down the scale even more, if you're loading 100 grain bullets for a bolt action 250 Savage you can get 80% of the speed of the bee for 50% of the powder.

And the 25/20 is more efficient still!!

Sheesh.... If one is going to carry a 30/06 lenght action, I would not see any benefit of the 25/06, AI or otherwise VS a 257WBY especially since we can get terrific brass without fireforming and the 25/06 is not going to get us to the speeds a 257WBY will achieve. A mere 15-20 grains of powder per round loaded is not going to make that much difference in cost to reload or recoil in my view.

Kenaiking is right that a 25/06AI might get sorta close, but I am pushing moly'ed 100gr TSX's at 3800 and I dont think 50 or so grains of powder is ever going to even sniff these kinds of speeds. My .02 since it was asked of us.

BTW, I am on my 3rd 25ROYwill probably not be without one again so long as I can get out and hunt deer sized stuff.

About 400 feet per second....

With sane and similar pressures and barrel lengths about 150 fps day in and day out.

25/06 AI with 26" = 3450

257 Wby with 26"= 3600

Anyone running either mucho more than that is running a tish bit in the red...grin

Dober

You're right....I was thinking 257AI...Sorry...

Aint no bigga casa grande to me...grin

Dober

It's amazing to me that you can get that big of a boom and the performance out of a 257Roy with the mild recoil....Not as deep of a voice as a 340Wby but just as loud...And you don't mind shooting it...

Heck I don't even mind the .340, as long as you're the one shooting it...grin

Seriously though, I've used a .340 quite a bit and have not found it to be all that caustic. But then again it's amazing what we can get used to.

It's a heck of a yote rig, you should make one up for those big old Texas yotes.

Dober

The 340 is hell on armadillos...

I have seen loads hitting 3700 often enough with a 26 inch barrel, my 27.5 inch barrel and Moly'ed bullets gets me to 3800 with safety margin to spare. I hit 4,000fps with trial loads but those WERE too hot, by quite a bit... Interestingly loads that hit 3900 did not show any of the mormal 'signs' of high pressure but I backed down to 3800 as I am reading more and more of how the old signs we used to count on being unreliable barometers. Figured 3800 was plenty fast enough and the cases last a long time at this speed. The deer think it is an awful load.