John Barsness posted this on a different forum:
There is some data posted on Hodgdon's web site.
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.
There is some data posted on Hodgdon's web site.