I've decided to build a 240 weatherby,I have a rem long action to use for the action.will be used for killin wolves,with 100 grain bergers,Question is what brand barrell and length? weight is not a factor,figure heavier the better.
The barrel manufacturer and choice of contour are all a matter of personal preference, can't help you there..
What I can help you with is the length and twist for the .240 Wby.
I have a custom .240 Wby that shoots the 105 gr bullets at 3380 fps under a stiff load of RL22. That's on the edge with these bullets. I haven't pulled them apart yet, but I know if I push them any faster they will fragment in the air.
No need to go any longer than 28", or twist it any sharper than a 9 twist.
I shoot both a custom 240 Wby and a custom 257 Wby. The 240 Wby is all you need for animals under 200# out to as far as you can hit them.
I use a 115 Berger in an 8 twist barrel and on a hot day or with a hot barrel I can get the bullets to blow up. Probably Joel is correct about a 9 twist being just right. You have your choice of some very good Berger or Sierra VLDs.
I built one for my wife and son to shoot about ten years ago. It has a 27" #4 Hart barrel on it. It is a one hole rifle at 100 yards. It will hold 1 1/2" at 400 yards. It is one of my best rifles. It is a very good rifle for your purpose. Weatherby brass just got so expensive we shoot the 240 gibbs more and the 243 AI. The gibbs is faster than the weatherby and the 243 AI a little slower. 25-06 brass and 243 brass way cheaper if you shoot a lot. The gibbs is the fastest you can go in a 6mm and have any sort of barrel life. I can get you some of my loads if you want to look at that one. I remember for varmints we were shooting the 70 grain nosler varmint bullets around 4100 fps out of a 28" barrel.
Predictions are difficult, especially when they involve the future