I use the Hornady 180gr SSTs in my Sendero and they seem to do real well. I just have a question, If you have a 300WM why get a 300RUM. I got the 300RUM for a paper puncher more than a hunting rifle. I did use it on one hunt this year just to try it out. Bigcountry which powder did you get the best overall reesults with. The Retumbo gives me good groups but I am getting more fliers than I want.