I tried the Retumbo today at 57.5 grains, 140 VLD, Fed 210M primers and could only get 2804 on the velocity. H1000 at 56 gr averaged 2825. I can't seem to hit the velocity others are posting with anything other than RL17. Shot a couple more with RL17 at 49.5 gr and the velocity went back up to 2972. I keep reading about temperature sensitivity in the RL17 and accuracy issues when you stretch out the distance. Id like to find a powder that gets me around 2950 and maintains stability.
So far, all the powders have been acceptable from an accuracy standpoint.