I have a 264 Win Mag Sense to and am developing loads for accuracy. As the 264 has ample case capacity and I generally like to have 90%+ fill, this would favor the slower powders. That said, I've tried some RL33 and noticed the heavy barrel is not after 1 firing on a cold barrel. Closely similar velocities with faster powders seem to put less heat in the barrel.
Q's: Assuming I find an accurate load with faster powders (IMR4350 is not bad), will the barrel life be better off with the faster powders or slower powder? I had thought that peak temp would be lower and favor the slow powder, but I'm having second thoughts on that theory.
The first gunsmith I used for a re-barrel had a dislike for any powders slower than 4350. He believed that slower powders eroded throats faster than 4350 and challenged whether any real benefit existed from that opinion. That was several decades ago now and I for one, cannot prove him wrong.
