Is the extreme series something new or is it just a new sales promotion ? Do the extreme powders really have lower velocity spreads, less temp sensitivity, and less lot to lot varation like they claim?

I had emailed hodgdon about extreme powders, also asking if they were double base or single base. They are single base. And supposedly have low pressure spreads

Not new, Varget was the first of the extreme powders, about a dozen years ago. I had a just about empty 8# of H4831- Made In Scotland, and replenished with 8# H4831Extreme- Made In Australia. I can't make any claims to lot to lot consistancy, but it is less temp sensitive than the older version.

The "extremes" are all made by ADI of Australia. They are chemically a bit different, number for number, from some of the Scottish, Canadian, Floridian, and other powders marketed by Hodgdon in the past. Hodgdon noticed in their testing that the ADI powders exhibit some less variation in burning qualities due to ambient temperature compared to other powders. They were not designed to be "temperature insensative", they just turned out that way (to a limited degree).

So, are they really less temparature sensative, or is it mostly advertising hype? I think the answer is some of both: They are marginally less sensative, but the real world difference is de minimus. Hodgdon's marketing people siezed on a characteristic that could be identified in the laboartory and used it for advertising hype.

I can assure you that if Hodgdon found another supplier of comparable powders using its old formulation, but at significantly lower prices than ADI, Hodgdon would drop the "extreme" hype in a heartbeat. So, you judge which is the greater factor, the powder's performance or Hodgdon's marketing hype.

In 40+ years of handloading, I have never found temperature sensativity to be a significant factor. Other powder characteristics are more important. As a result, I ignore the advertising and look for what works (and at the price!)

quote:

The "extremes" are all made by ADI of Australia. They are chemically a bit different, number for number, from some of the Scottish, Canadian, Floridian, and other powders marketed by Hodgdon in the past. Hodgdon noticed in their testing that the ADI powders exhibit some less variation in burning qualities due to ambient temperature compared to other powders. They were not designed to be "temperature insensative", they just turned out that way (to a limited degree).

I can`t quite agree with this. I`ve found ADI (Hodgdon extreem powders)to be better in than some in respect to temp induced velocity variations but more on the 70* F - 100* F range and not from 70*F-20*/30*F temps. They don`t all appear to give the same level of resistance to temps either, depending on powder type, cartridge and bullet wgt.
ADI claims they are designed to resist temperature extreems.
From the ADI web site,

quote:

All the rifle powders are single perforated tubular propellants of single base composition based on ADI's experience in developing powders for the Australian Defence Forces' use in extreme climatic conditions. As a consequence all the rifle powders have, as a feature, low ballistic temperature coefficients - ie. velocities and pressures do not vary with ambient temperature like most of the other powders available for reloading.

http://www.adi-limited.com/handloaders-guide/about_adi.asp

I load H-1000 in the .300 Win. I have coronographed (Oehler 35)the load in temperatures ranging from 27 degrees to near 100 degrees. The velocity hasn't varied 10 fps. and accuracy is very good.
FWIW,
Jim