I'm currently building a 260. I spent some time talking with Tim North of Broughton Barrels and decided to go with his 3.05 contour. He had me order it to be finished at 24", then I'm having my smith cut 1" extra off the breech end, so it will be finished on the rifle at 23". Tim felt this would maximize stiffness and reduce weight.
FWIW, Charlie Sisk in his book "Selecting and Ordering a Custom Hunting Rifle" states on pg 148 "My suggestions for maximum barrel length with regard to proper stiffness in relation to contour are as follows:
#1 20"
#2 21"
#3 22"
#4 24"
#5 26"
405wcf
