I have used Varget with good success in the 243, but for some reason had low velocities using it for the 22-250. I get good accuracy and velocity with H380. As I recall, the owner of Hodgdon shot the 22-250 back when it was still a wildcat. He had an some old powder that had been used in WW2. He would load 38.0 grains and got perfect accuracy and velocity, so he named the powder H380. At least that is the story that I read. I have tried 38.0g in my 1/10 twist Ruger American and it prefers 39.0g and shows no signs of pressure. The last time I took it to the range it shot a .78" group with an average MV of 3518 fps. The Standard Deviation was 21 fps. This was using the 55g NBT.
NOTE: I am not a new member. Previously I was Calcoyote but, when the forum underwent the big upgrade a couple of years ago I was no longer to login so I was unable to post. I tried emailing the moderators, but I guess there was nothing that could be done, so I lost all my posting history. Still love this forum though. It is good to be back.