Well, here we go I found a good deal on a Factory 24" 270Win tube.Thinking of cutting it to 16.5" then rechamber it to a 270 Weatherby Mag.I also picked up another 26" 300Mag tube that may soon be a 17" 300H&H just to see if it is as good as the 300Mag.What do you guys think..? Of a 270WM.

IMHO, i would look at the wsm case instead of the weatherby. Cases arent nearly as expensive and in that short barrel, i think that the wsm case will give you VERY similar velocities.

Did ya buy the barrel? Are you gonna do this project??

Remember the longer the case, the less rifling the bullet has to travel. I think you'll have better accuracy with more spin on the bullet.
Just my opinion.
Bill