105's seem to go to sleep in the 3300 fps max. 105's do not shoot well past 3300 as a general rule of thumb.
Weatherby brass sucks for holding pressure on the top end, and your expectations are to push the top end+.
You could do this with a 244 AI and save a bunch of barrel life.
If you go with the 244 AI or the 6/06 AI, you can push the limits on pressure by using PMC 7x57 brass or PMC 270 or 30/06 brass. Lapua is another option.
One thing that you should remember is that VLD bullets will not stand a .300 freebore.
Not quite sure what you're implying when you say Wby brass sucks for holding pressure on the high end. Not trying to be a smart azz, just curious what you mean by your statement. I run both my 257 and 270 Wby's on the top end and have had no problems. Just shorter brass life as with any cartridge, but nothing excessive.
As for the Freebore, the 240 doesn't run the standard .378 of the other Wby cartridges. It's quite a bit shorter. Don't know the exact number, .169 possibly,as someone mentioned earlier.
