Here is what I came up with in my 27" RUM with 215's. H1000 and Retumbo were the only powders I was willing to try because of their temperature insensitive properties. I seated bullets with .005" jump which makes the COAL 3.880". With Retumbo I started at 93.0 which produced 3144fps and then moved up to 96.0 where I definately hit the Retumbo pressure spike at 3252fps. Never saw any consistency with Retumbo. With H1000 I started at 90.0 which produced 3086fps and moved up to 93.0 at 3197fps where I felt this was max in my rifle. I ended up settling on 92.0 grains of H1000 which produces 3140fps with less than 10fps ES. Accuracy seems to stay inside of .75MOA with a barrel on it's way out. I have shot it at 765 and 1100 yards now and the vertical dispersion was only about an inch at 1100. Very happy with this load so far. I imagine with 30" of barrel you shouldn't have a problem running in the 3200fps neighborhood. Hope this helps.