Not sure what you have on hand but Retumbo would narrowly be my 2nd choice after RL26. 3rd choice would be H1000. I know there are others but I have done a significant amount of reloading for the 6.5 PRC with the 156 and RL26 and Retumbo are a great fit. Retumbo likes the barrel to be 24" or longer. H1000 if barrel shorter than 24". RL26 works for any length barrel.