Powder Temp Thoughts

[praetorian97]

Gets cold in my garage. Probably High 30s Low 40s at the coldest point in the winter.

Before I reload I start up a heater and let the garage get to comfy temp where I can wear shorts.

Now should I still worry about letting my powder get cold even though I reloading it at room temp?

[PawPaw]

No, many of us store powder in a refrigerator, mainly to control humidity rather than concerns for temperature variances. I don't see any problem at all with your plan.

[wncchester]

It would be best if you let your powder rise to room temp before opening the container; anything that's colder than the air will collect condensation. Probably wouldn't be a big thing but it's easy to avoid.

[mehavey]

+1 PawPaw
+1 Wncchester

That about covers it for practical purposes.

[praetorian97]

Thanks guys. I'm thinking about storing my Chargemaster indoors just to keep the cold away from the electronics but I have too much powder to store indoors.

[briandg]

Powder that is extremely cold may actually shrink a little, so volume measurement may become problematic if you are using a very fine ball powder and running it to max loads. Always weigh.

For various reasons, I don't like the idea of storing powder where it can go below freezing, or far into the 40s, even, several problems have been listed already. I never kept my powder in cold storage, my garage, when I loaded there. it was in a closet in the home.

I just advise against it. YMMV.

If you can't store it indoors, at least plan ahead, and move whatever you will be using into the home to stabilize for a day or two before using it. I'd do the same thing for a measure.

BTW, you do keep that heater away from the table, right? Very, very small risk, but a small risk, nonetheless.

[Major Dave (retired)]

NOT at the time of loading, has a significant effect on velocity achieved.

So, if you go to the range with a certain reload to test it for velocity and accuracy, the results will be valid only within a limited temperature range centered on the air temperature on the day you were at the range.

For example, this summer in East Texas we had over 75 days of temps over 100 degrees. But during deer season we will have overnight lows mostly in the 40's, and highs in the 60's. If I had a hand load that produced 2,950 fps MV @ 105 degrees, what velocity would I get @ 45 degrees? Slower, that's for sure.

On the other hand, if I made up a load that produced 2,950 fps MV on a 45 degree day, then went hog hunting with it in July (105 degrees), that would possibly result in an unsafe high pressure load.

As for the effects of storing powder in refrigerators, I don't think that is a good idea. Looking at a one pound can of IMR 4320, this info is given: "Store in cool, dry place". Note that the word was "cool", not "cold". An unheated garage during the winter sounds like it doesn't fit the definition of "cool" to me.

I'm just saying.

[farmerboy]

I agree with brians comments. I've always stored my powder indoors. My neighbor has prob 20 something pounds I'n his reloading room so I don't know what you mean by saying you have too much powder to store indoors?

[praetorian97]

Too much as in where am I going to put it.....

Closets are full. Gun Locker is full of guns.

Dont think the GF would like it in the pantry next to the flour and sugar

One thing I think of the most is what about these guys in Iraq or the Mountains of Afghanistan. I cant see there ammo being stored in climate controlled rooms.

Hows a powder in a brass container better protected than powder in a container from the temps.

[briandg]

Ammo is different from powder in that the powder is fully sealed in completed form. It will never be exposed to air, it has been measured and assembled already. Something important to remember as well, is that the loads have been designed to work safely year round, and under any storage conditions.

You can probably go ahead and store your powder anywhere, really, that you could store ammunition, as long as you never use it except when it is at nominal room temps.

There is one thing to remember: smokeless powder is a nitrate based explosive that isn't completely chemically stable. Temperature extremes and changes can degrade your powder. All powder and ammunition should, wherever possible, be stored under the same conditions as food or wine. 40 - 60 degrees or so, and in th case of powder, dry. You do that to delay chemical deterioration for as long as possible.

[wncchester]

Chemical changes occur faster at high temps, slower at low temps. Liquids 'freeze' but solids do not; powder (and primers) are solids.

Anyone wanting the absolute longest lasting powder should store it at the lowest possbile temp and then allow it to warm to room temp before decanting.

"Changing" temps mean nothing to the life span of inanimate solids other than the accumulated effect of intermittently being at a higher temp when it's being used.

I still have a bit of the .30 Carbine ammo I loaded in the mid-60s. It works as well today as then and I've done nothing special about storing it in my garage.

[JayCee]

I don't understand the logic of storing powder in the refrigerator to control humidity. Unless you store your powder in an open container, it won't be affected by external humidity. If you store it in a totally sealed container, you could store it underwater with no ill effects.

[Unclenick]

The refrigerator's cooling system condenses water out because the evaporator coil is cooler than the air it is chilling. Same as a dehumidifier in that way. The condensed water is then either drained or becomes frost that is melted and drained off during the defrost cycle. The drains usually go to an evaporator pan so condenser coil heat can dry it. Either way, the refrigerator is constantly removing moisture from the air inside, which is why vegetables mummify in a refrigerator if left long enough.

Chemical reactions do tend to slow with temperature, though I've heard nitroglycerine becomes more sensitive if frozen. I can't imagine that applies to it in powder, though, as powder is, as already pointed out, carried into all kinds of conditions.

For that reason I don't see why freezing it would promote deterioration, but I'd check with Hodgdon's techs to be sure I'm not missing something. I expect condensation after opening is the main concern, though. Selecting the can you want to use and letting it heat up to shop temperature before opening it is important. You don't want to weigh water with your powder and get an undercharge. And I'd allow hours, not minutes, for it to equalize to room temperature.

[briandg]

There is a very valid reason not to freeze. It has nothing to do with water.

Powder is a mixture of chemicals. every chemical has different rates of expansion and physical properties. most powders have several coatings and additives.

Long, frequent cycles of repeated freezing and thawing will result in breakdowns in the structure of that carefully extruded and treated, or treated ball powder that may cause changes in performance.

Is that an absolute certainty? Yes, eventually, but who knows what it would take to deteriorate your powder/primers?

I'd like to see an experiment. Somebody in a cold climate should stick 500 rounds of reliable .22 lr in a clear mason jar, and leave it outside for a decade, in sun, wind, and freeZing temps. Starting around 5 years, start function and accuracy testing, and see how long it takes for that dry, but cold and fluctuating environment to destroy powder/priming compounds.

[Unclenick]

Consider the amount of cold exposure ammunition had in winter in Korea and on the Russian front in the big war before that. Soldiers carrying it in and out of heated shelter several times a day in that kind of weather probably accumulated hundreds if not thousands of cold cycles on some cartridges. Not to mention aircraft hauling it up and down into and out of subzero temperatures. I think the fact every major constituent is a nitrated organic compound and the fact grains are small enough that temperature drop from surface to core is small, means there probably isn't a lot of differential thermal expansion with change in powder temperature. So normal winter cold by itself can't really be expected to be a big problem for it. Cycling it in and out of liquid nitrogen may make a difference. You could try that experiment to see if you can break any of it down, but normal winter temperatures aren't quite that cold.

Heat would concern me more, but even then it seems to take a fair amount. When I took classes at Gunsite we were told a couple of the instructors had discovered you could destroy modern non-corrosive primers with as little as one season in the trunk of a car that was routinely parked out in the Arizona sunshine. No problem with the powder reported, but I'd expect its shelf life to be considerably shortened. In that case, just look out for the usual signs of breakdown.

[briandg]

I don't think the question is so much whether the round will go off, but how well it will function. going through a year of temp extremes isone thing, but 15 years or so of the same is a whole different matter. In the long run, I don't expect that the powder or ammunition would be unshootable, but it would wind up inconsistent and inaccurate.

I don't think that there is any doubt that a few liquid N to 125 degree treatemnts would damage the structure of a powder.

Like I said in the post, I don't know what the actual eventual effect would be. it's undeniable, though, that there would be an effect of some sort, and the more complex the powder's make up is, the more susceptible it will be to damage.

It doesn't surprise me that primers are more vulnerable. there is very little compound, and the compound itself is unstable.

[Unclenick]

The father of a friend of mine liked to say there is no point in arguing about a fact. You just look it up. So I gave Hodgdon a buzz to see what they had to say. The correct answer turns out to be, "it depends".

The Hodgdon tech had a couple of extreme examples. One is IMR powders that have inexplicably gone bad in a relatively short time despite being kept in good conditions. I've seen a couple of fellows mention having IMR4350 that started smelling bad and making red dust in just a few years. They have no explanation, but the tech did say they've tightened quality and consistency since taking over distribution of IMR, so perhaps they'll have accidentally fixed the issue.

At the other extreme, the Hodgdon tech mentioned a customer whose only available storage space is an abandoned car in a field behind his house. He's stored powder out there for years and never had a problem. They don't recommend this, but it has worked out at least that once, and probably more times they've not heard of.

Some other tidbits I picked up from the Hodgdon tech:

The Extreme line of single-base stick powders is their most stable line, and they expect that will extend to storage life. Their literature boasts that its burn rate is constant from 0°F to 125°F, but he said they actually test it from -40°F to 140°F and it burns very consistently across that range. He has no problem with it being exposed to those extremes.

Since the powder comes from Australia, it is probably shipped in standard shipping containers. In hot sun those can reach 170°F inside, so it must be able to tolerate that for at least 2 weeks of travel outdoors and still be in essentially fresh condition when it arrives. Indeed, 2 weeks exposure to that temperature without substantial deterioration is a standard spec for appliances to be able to tolerate in shipping, and you can figure anything delivered by unrefrigerated train car will probably have to be able to meet it.

Hodgdon said their spherical propellants are the least tolerant of adverse conditions. These are double-base, and that's likely a big part of the reason. IIRC, the military surpluses out double-base powders and ammunition loaded with it after 20 years, but allows 40 years for single-base powders like the IMR stick powders. That would seem to substantiate the notion double-base is less stable. Apparently it is also the most temperature sensitive with regard to burn rate. The IMR powders are inbetween the Extreme line and the spherical propellants with regard to temperature sensitivity.

Another tidbit, gleaned elsewhere is with regard to moisture. You are always told to store powder in a cool, dry place, but Alliant maintains a sample of the first lot of Unique ever produced. It is over a century old now, and is kept under water. Periodically they dry out and test a sample. It is still good, despite being double-base. Water apparently does no damage. The concern is just that your charge weights will be off if enough water is picked up.

So, will the garage be a safe place to keep powder? I guess it just depends.

[briandg]

So, it seems that what you learned is that it isn't stable, but it's pretty stable, stays stable for a long time, and except for extremes of temperatures that aren't usually going to be found in an attached garage in most places, it will remain stable for years.

I guess maybe it is safe to leave in a garage and use for a few years.

in most cases.



The extreme, with no nitroglycerine, would be most stable because of just that fact. It's an inherently more stable compound, just the nitrocellulose, and a simpler mixture. without the added nitro, how do those add up for velocity+pressures compared to a dense double base ball, i wonder?

Thanks for the research. I'd forgotten about that story about the unique. It's true, moisture doesn't have much that it can do to smokeless powder; it's plastic. it won't absorb. It may wash off coatings and so forth, but it shouldn't ruin it just because the stuff got damp.

[hk33ka1]

Some ammo companies and many reloaders stored powder in old UNPLUGGED refrigerators as a powder magazine. I never heard of anyone storing in a cold running fridge. A running one will have plenty of humidity inside.

[DBR]

Unclenick:

Apparently we've gotten conflicting info from Hodgdon. I spoke with one of their techs about three months ago. He said the ball powders had about twice storage life in loaded ammo vs stick. I was inquiring about H322 (short cut stick) vs H335 (ball) for 5.56 loads. I wonder if they really know; 20 vs 40 years (his times) is a very long time to speculate.

What the tech told me was the manufacturing process made the ball powders "cleaner" ie less contaminants hence the longer storage life. Might just be something he inferred from what he had heard and not a fact. I have spoken with "techs" at several powder companies over the past twenty or so years. They are not engineers or chemists. Their best knowlege or opinion should not be taken as gosple IMO. They tend to fill in the gaps in their "facts" with hearsay or whoever taught them did the same.

I have unopened metal 1# cans of powder here that my father bought in the 1960's. They have always been in a normally heated dwelling. I opened one and I can still smell ether. These are stick rifle powders.

I believe it is Bullseye that has the original 100 year old sample stored under water for reference and it is not wet. It is in a sealed container and all the water does is keep the air away and maintain constant temperature. Maybe there are samples of Unique stored in a similar fashion as well.

I guess the most accurate info you got from the Hodgdon tech was "it depends".

[Unclenick]

Hk33ka1,

Actually refrigerators desiccate things, as I explained in my earlier post. The evaporator condenses out moisture. Leave a loaf of bread in one without the bag closed and you'll quickly see the effect. The moisture you associate with refrigeration is condensation that forms on the outside of refrigerated objects after you remove them into warmer, more humid air.


DBR,

I've read conflicting information on storage periods. Originally it was single-base powder that deteriorated most quickly because nitrocellulose deteriorates spontaneously. One of the reasons the spherical propellant process was developed was it could recover good nitrocellulose from old deteriorating military stores of powder and reuse it after introducing carbonates to neutralize the acid breakdown products in the original powder (see Hatcher's Notebook on gunpowder). Apparently such deterioration is especially an issue in physically large grains, like artillery propellant for battleship guns, where the center is distant enough from the surface to concentrate breakdown products in the core. Since those products promote further deterioration, their concentration causes break-down to snowball.

Rifle propellant grains are small, though, and after they began adding diphenylamine to stabilize it, properly made, it becomes quite stable for a long time. Recently a fellow on the CMP boards got hold of some M1 Ball ammunition from the 20's or 30's and says he pulled a number of rounds and found the IMR1185 in them was still in good shape. On the other hand, that board also has photos of a Garand blown up and with even the receiver ring split by attempting to shoot some 1940’s vintage military ammo through it that had destabilized in the wrong way. This is odd because usually powder gets weaker as it deteriorates. Just not always, it seems. So we have yet another example of “it depends”.

IIRC correctly, Bullseye changed a bit over its early years, with the final formulation and packaging being established in 1913. The Unique formulation (until the change in 2000 to make it cleaner burning) was apparently established in 1890 as a Laflin & Rand powder, and an early version of what was to become Bullseye followed. I’ve heard from several sources that it is the older Unique that is stored under water and dried to test periodically (I can see no reason a sealed container would be stored under water; it would be in sand if explosion damping was the concern). I tried to call Alliant today to confirm the storage method and the powder so stored, but their fellow who handles technical questions had the week off and won’t be back until Monday. I’ll try again then.

[Jim243]

Now should I still worry about letting my powder get cold even though I reloading it at room temp?

No do not worry. The process that breaks down powder is oxidation. Keep it sealed and away from any extreem heat that would affect a chemical reaction with the oxidizer within the powder.

The reason most say that mil-surplus is sealed both at the bullet and primer is to keep out any water or moisture, while that is a good reason to insure that the powder will burn if you dry out the powder, it will burn. But for storage for long periods of time you want to keep as much oxygen out of the case as well. That is why rounds produce for mil use 50 years ago or longer will work, HOWEVER the outside of the case has no such protection and oxidation of the brass will weaken the case and web of the case and that is why you have failures with older mil-surplus ammo.

Since most reloading is done on a basis of volume, it would be a good idea to bring your powder to room temperature before setting everything up.

Jim