going all the way way back to the OP,
Yes I've tried IMR-4166. I developed a load and went to the chronograph to confirm.
I use a 150gr FMJ over 42.2gr of IMR-4166 in a Federal once-fired case, lit it with a CCI-34 primer, and it got me in the mid-2600's MV from a 20" barrel. The group size...