I am watching the topic. It has been interesting about the powder combinations for this cartridge with 195's. I just started to use retumbo and at 80 grains I was running a 195 at 3003fps. I have been interested in temperature sensitivity since I reside at 1000 ft elevation and planning on hunting for elk where I could be at approximately 10,000ft. From the numbers that I ran if correct a 195 at 3000 FPS still carries lots of energy compared to most calibers. I am thinking that I may be content with retumbo due to temperature stability, possibly a little more barrel life where I can shoot a couple more rounds to understand the capabilities and limits of the cartridge and it seems to shoot it well. Just my opinion.