Don't know for a fact but I suspect the weatherby action is not much if any stronger than most other's. Think I read years ago that the secrete to the so called high pressure loads in weatherby is the bullet jump to the lands, have read there a lot of free bore in the Mark V. All that free bore should increase case capacity without throwing the cartridge over the pressure limit. I think that a reason no Weatherby cartridge is used in match shooting, match accuracy doesn't seem to be there. In fact, weren't the origional Weatherby rifles Mauser's? My own idea about the Mark V action is it's more of a sales pitch than anything. I think back in the 70's Sauer was marketing a rifle with a similar action but not in Weatherby cartridges.
I think I've mentioned my old 7mm mag from years ago on here. Tried cutting out the lands to allow the 160gr bullet to be seated out with the base of the bullet at the base of the neck. Was looking for more accuracy and got it but also noticed that the max load increased by two grains using N205 powder! Has to be increased case capacity doing that. What wasn't around then was chronographs so I could actually record the before and after velocity! Wonder what would happen if a 30-06 was opened up to provide more free bore? My old 30-06 has a pretty badly worn throat and the bullet's, Hornady 180gr BT's are seated to the base of the neck. If the barrel wasn't already so worn I'd try it just to see. These days I do have a chronograph. Be interesting just to see!
I don't know what would happen with say my 6.5x55. magazine won't let me seat 140gr bullet's out that far and I can't reach the lands with the bullet. Then wasn't the origional loading a 156gr bullet? Perhaps they couldn't get a long enough action to handle shorter and longer bullet's and saw the thing as a big game cartridge so to fix that went with a lond throat. Increase case capacity and still be able to use shorter bullet's. The long action's in American rifles I've tried won't allow seating bullet's out to much. Had a 700 like that in 6mm Rem and because of the magazine couldn't reach the lands with the bullet's. Finding that pressure change in that old 7mm mag, an L61R sako, really surprised me then.
Had to go look. That old 30-06 is a 1903 Springfield and bullet's are seated to the max in the magazine. But at that length they need to be loaded bullet first through the action or the bullet hit's the front of the action.
