I'm not JB either but, I went to IMR 4451. I don't see velocity loss when it's really cold, which I saw with IMR 4064. I never had a problem with high temps. In my experience the "copper eraser" really works.
The Enduron IMR 4166 is just a hair faster than 4064 and seems accurate in my 308.
Scuttlebutt is that Enduron powders are made by General Dynamics in the US rather than ADI Australia. I dont' really know.
If they made an Enduron at IMR 4895 speed, It would become my "everything" powder.
