I just come across a large quantity of this powder but I can't find any data on it. I know it is an old ww2 surplus military powder. Does anyone know if there was any data published for this powder?

Wyatt, I've never heard of H-320. You sure it isn't H-322? Jim

I suspect it is H322, a great powder in the 222, 223 and 6x45, set all kinds of accuracy records some years back...I use a lot of it.

This powder is marked h-320. I called hogdon and they were very helpful. They told me this was a surplus powder manufactured in the 1940's and the burn rate is equal to IMR 3031. I think I'll give it a try. Thank's guys.

I bought some H-320 about 8 years ago. It came in little white paper bags, about i pound in each. I too called Hodgdon and they told me the same thing that the burning rate was similar to 3031. I bought about 10 lbs for something like $20. I was in my reloading room this past winter and noticed a vinegar smell. I did some checking out and found those little bags of H-320 had deteriated, spilling powder all around the powder area. The smell came from the powder. I took the whole lot of it and scattered in in the back woods in the snow.

The interesting thing is that I ran into an old shooting buddy this past spring, and we were chatting about reloading. He mentioned that his bags of H-320 degraded too, and he had to dispose of the powder. We bought the powder from the same guy, and it degraded at the same time! I'm guessing the manufacturing date was late 1940's or early 1950's.

Beware with storing this powder. I'd also make sure to clean your barrel well, just in case there is anything in the powder that may corrode the barrel.

Be careful with loaded ammo. It may not store well. It's not just my findings, but from two people. Granted, both of us bought powder from the same lot-but it is at least some real life feedback with Hodgdon 320.

I never shot the stuff, so I can't comment on accuracy, burn rate, pressures or the like. If I came across more Hodgdon 320 " for cheap", I wouldn't buy it.