Jerry funny you should mention H4350... because I've been thinking of trying it with one of my 6.5's... I shot some chrony'd tests late summer and surprising enough the ES & SD was pretty stable single digit stuff... surpised the heck out of me because looking down in the case the powder doesn't come anywhere near the shoulder...
I just heard the stuff was barrel burner quality... I'm not sure about it's flame rate either... it's up there but that's all I know... I heard a story that the AMU stopped using it because they suddenly starting replacing a lotta barrels for their crew... dunno... might just be a story without substance...
again if it shoots and groups barrel life is down on my list... might try testing it some more come spring...