Hodgdon just announced three new extruded IMR powders that are temperature resistant and contain a decoppering agent. The three powders (IMR 4166, 4451 and 7977) are roughly in the IMR4064, IMR4350 and Retumbo burn-rate ranges, and are made in Canada at the plant that makes other IMR powders.
I got to thoroughly test IMR4166 this summer, and it worked as advertised in a bunch of rounds from .204 Ruger to .45-70. Data for all three "Enduron" powders is now up on the Hodgdon website.
Don't know about pricing, but assume it will be in the same range as the other IMR powders.
Good to know. I'll be doing some 4166/8x57 loading over the winter.
