I have a 264 winnie that used to belong to my grandfather, it is built on a VZ 24 mauser action. Anyway I want to start loading for it. I have a pile of 140 gr speer grand slams. My Speer book lists Imr 4350 as a suitable powder among others but I have several pounds of H4350 I would like to use. The manual lists 55.0 grains as max with the IMR, where should I start with the Hodgdon's? Thanks for any help.