I would not get a factory 240 Wby. They only come in 24 inch #2 profile barrels with a 1-10 twist. You really canít get all of the benefits of the case with that barrel length. I also assume you have some experience reloading because shooting factory ammo is going to burn some money and provide little that the 243 wonít do reasonably well.
A 30 inch heavy contour barrel in about a 1-8 twist or maybe a 1-9 twist will stabilize the 105 -115 (and most likely the 120 grain) VLD bullets. That barrel lenght will burn a lot of powder.
If you get a minimum SAAMI chamber with no freebore throated to a VLD then the cartridge performs very well. You may not be able to use factory ammo anymore because of the pressure without the freebore
I had a 240 Wby 1-10 twist medium profile 26 inch barrel taken off of a FN action and the current 1-8 twist 30 inch barrel installed. It was restocked with a Joel Russo stock.
At a few hundred feet above sea level, I run a 1000 yard drop of 21.5 inches with the 115 Berger
Norma/Wby brass is very good quality brass but it is a little softer than most. That doesnít bother me because after I have driven 3000 miles to shoot some antelope, I really donít worry about the prices of a few cases that I may ruin by loading up to max pressure.
On eastern whitetail deer and antelope the gun in the configuration I shoot is probably good to exactly 1000 yards and on a calm day maybe I might stretch it further. The best I have done so far is 860 yards on antelope.