I just ran some Hornady 162 gr SST and Retumbo out of my 7mm Rem Mag through a chrono. They were loaded to 10 thou off the lands at 3.365" OAL. I got good accuracy at 69 gr and 2925 fps, 70 gr went just under 3k about 2980 fps also with good accuracy. The next increment group of 71 gr went 3175 fps! and the accuracy went south. That jumped up fast and wasn't what I was expecting at all. I had rounds loaded to 75 grains... I will be pulling those rounds to salvage the components. While I may may work a bit more with the Retumbo about 69 gr I'm not sure I like how touchy this powder is at the top end.
