With heat treated WW metal, you can take a 240gr cast GC bullet, load it with the same charge, as indicated in the manuals, as a jacketed bullet with the same weight and get higher velocities, with less pressure.
Of course this will only stand if the bullet is properly fitted to the bore.
Sorry about the confusion, I was rushed out of the house and was trying to get my thoughts out too fast. It didn't make sense to me either when I went back and reread it when I got back.
As far as stability, the 315 gr LBT LFN I use, has gone through 12" Mesquite trees and 15" creosote posts with very little deformation. I don't really care if these do not expand. The wound channel is larger than most hunting calibers with jacket bullets, on deer size game.
I'm not sure what you mean by "tinning of the barrel". I am not familiar with that term. But, as far a leading, there is little to none when using the heat treated GC bullets, when properly sized to the bore of a particular firearm.