It will deteriorate a lot faster under those conditions than if kept cool. Off the top of my head, the Army uses a temp somewhere near 150�F for the accelerated aging testing.

Powder usually doesn't lose "strength" noticeably as it ages, and more commonly the pressure and velocity of cartridges loaded with deteriorated powder go UP. Supposedly this occurs because the molecular chain length of the nitrocellulose goes down with aging and breaking of bonds. This results in embrittlement of the powder, which can shatter on firing, exposing more surface area to the hot gas and thus burning faster. Military ammunition and powder in storage is periodically tested ballistically as well as the chemical tests I mentioned above, and a common reason for taking it out of service is because pressures have risen above specs.

The US Army estimates smokeless propellant stored properly should have a useful life of 50-75 years, but storing it under high temperatures (as encountered in a tin shed in the summer sun, attic, parked car, under a tarp on the range, etc.) can easily bring powder to the red-fuming stage of deterioration in 2 months or less.

This likely explains things like the batch of 1942 Turkish 8x57 I have that's clearly on the high pressure side. Who knows how it was stored? You can bet it wasn't refrigerated.

I was surfing the net last night and caught a post by our honored colleague, Ricochet. Ric, correct me if I'm wrong, Sir, but as I understand it, in the near future, the gummint is going to start destroying all the milsurp powder that is currently available. Did I read that correctly? If that be the case, I'd sure like to know when that's gonna happen. Might be a good idea to stock up on our favorite flavors while the gittin's good. I've become very fond of my 7383, 4895, 860 & 820.

That's already the case, since sometime during the Clinton Administration. We're buying stocks on hand that have been around for a while. No more's coming. Surplus ammunition can't be dissassembled and the components sold. It's all incinerated now, and only molten scrap metal comes out. My information's off of Hi-Tech's and Jeff Bartlett's websites.



I'm sure they'll continue offering bulk powders from other sources, like the Czech and Chinese equivalents of powders sold by Accurate Arms that they presently carry. But the US GI numbers will disappear when stocks on hand are sold.

Ric,
That's what I was afraid of. I guess I'll have to invest in a stock of what I think I'll need for the future.

My thinking exactly.

Hey puncher ,how much 7383 can you refrigerate. roger

The concern with keeping large bulk quantities of ANY smokeless propellant is that they all do deteriorate, faster at higher temperatures. Their natural decomposition releases heat, and also releases oxides of nitrogen that catalyze more rapid decomposition. If the bulk of the powder's great enough to trap heat from the decomposition, a "runaway" condition occurs and the stuff self-ignites. There have been several major disasters over the past century or so with battleships, powder storage facilities, arsenals and such going up in a huge column of flame due to autoignition of smokeless propellants. (The Maine probably blew up due to its "cocoa powder" similarly autoigniting due to oxidation of the tarry components of its toasted rye straw "charcoal.") That's why it's safest to store large quantities of propellant away from dwellings in a cool place with at least one side of the storage container that'll pop out easily without building up much pressure. And it needs to be checked frequently for signs of deterioration like "red fuming." That can be transient and disappear, but the powder's already reached a danger point. The military and others responsible for storing large amounts of powder keep samples under observation at a higher temperature than the stored powder, so they can recognize danger signs before the stored powder goes. They also monitor the remaining amount of chemical stabilizer in the powder, which gets consumed in neutralizing the NOx fumes. When the stabilizer goes, the powder's unsafe to keep.

I stored about 20 lbs of powder in a shed all summer in AZ. It was hot - probably an average of 95 or 100 degrees.

I shot some last week (H1000) and it seemed to work wonderfully. I used to maintain two residences, and now have all powder in one.