H1000 is actually great in the 6.5x55, with 140s and up. I helped a guy develop a load for his 700 Classic with a 30" Pacnor, he was getting 3140fps with 53grns, in Lapua brass, with CCI 250s. RL26 or Imr7828 ssc is better, but he had a 8lb jug of H1000. I run 51.6grns of RL26 under 140 ELDMs in Lapua brass, with Fed210Ms, runs 3112fps, from the 26" Mcgowen on my Savage 116 action. 7828ssc would come close, but was hard on brass. I wouldn't use anything over 55k psi loads in the older inferior actions, but 65k psi is fine in modern actions.