I have had a can of this for a while now, just haven't tried it yet, it lists a smokein 22-250 load with a 50 grn bullet

I tried it in my 24" barreled 7-08 Rem and hit book velocities with the 120 and 140 gr loads with no signs of excess pressure, very low SD and good accuracy for non-tuned loads. It is a very short granualed stick powder that reminds me of Benchmark and flows from my measure like ball powder.
It definatly warrents further developement in this cartridge (708) in my eyes. I give it a go in your 22-250 you might be very pleased.