I'm gearing up to shoot a 6.5 Rem Mag orphan cartridge. From what I can see based on cartridge length and case volume, it is almost identical to the more currently popular 6.5x284. I am wondering about powder choice for these cartridges, assuming there is no substantial difference. I don't believe that powder has any magical accuracy properties, and the criteria for choosing powder is that it has a burn rate that is efficient, the SD of velocity produced, and ES is low. A secondary criteria is that it does not produce excessive heat that will accelerate barrel burning. With this in mind my short list has come down to H1000 and VV N165. The problem is that neither seem all that popular. Or perhaps what experienced users really use and what it posted on the internet is not in sync... I like Hodgdon extreme powders for their temperature insensitivity. I think that is one factor that reduces real life ES and SD due to cooking in the chamber. And if you believe the numbers VV N165 is one of the lowest heat powders on the market, which would suggest it may be easier on the barrel. And based on Nosler published data the best burn rate for producing velocity for the 140 grain class of bullets is RL-22 and RL-19. Based on Vihtavuori burn rate data, that puts H1000 and VV N165 right on the money for most efficient. So, now my question. Do you have experience with these two powders? Can you recommend them over the more often used powders like H4831 and H4350's?