shelf life

[oldbear1950]

any one have any idea how long a box of reloaded ammo can set before you shoot it?

I have located a box of 45-70 I loaded in 1983, when I was stationed in Kodiak, Alaska, was loaded for a Marlin 1895. I do not have that gun anymore, but do have a Henry 45-70. was wondering if there would be any problems. Is not hot loaded or anything like that

does hand loaded ammo, have a different shelf life than factory ammo?

[AL45]

From everything I have read, many decades if stored in a reasonable environment. 1983 doesn't seem too long ago to me. That was the year I graduated High School.

[jetinteriorguy]

I have shot reloaded ammunition that was over 20 years old and had no issues.

[Wag]

You should be fine. Go shoot it.

--Wag--

[Woody'sDad]

I have a few boxes of 30-06 I reloaded when I was 15 years old and now am 74 so you do the math---every year around the first of Jan. I make it a point to grab a few from one of those boxes and head out back to light them off--never a FTF

Now I don't run them over the chrono or see where or how they group but they do fire off reliably.
They have been stored indoors and in a 50 cal ammo box for at least the past 40 years so they are kept dry and with a steady humidity level

Guess I consider them last resort ammunition and they will probably still work long after I don't--LOL

Gary

[FITASC]

I have some of my reloads from 30+ years ago and some factory from 40; no worries

[Shadow9mm]

Assuming a cool dry place, id say over 100yrs +

[Paul B.]

I still have a few boxes of .270 Win. I loaded up with 150 gr. Sierras, Winchester brass and primer and Hodgden surplus 4831 that I loaded for my first .270 back in 1973.. Last time I shot any was about ten years ago and they shot just fine. I suppose I should just dig they up and break them down but why? If they still shoot good, hunt with them or at least use them for range fodder.
Paul B.

[Unclenick]

Originally Posted by oldbear1950

does hand loaded ammo, have a different shelf life than factory ammo?

It can. The canister grade powders sold to handloaders of of unknown effective age. Unlike the bulk grade powders sold to the military and most commercial manufacturers, which is the output of a single production run, the canister grade is usually a mixture of different age lots. This happens because most handloaders don't have pressure guns and must rely on published load data. For that data to be valid, the burn rate variation of the powder must be fairly uniform from lot to lot. Bulk powders are not uniform enough, so when powder is to become canister grade for handloading, its burn rate is tested to see how far off it is from the nominal burn rate used for recipes, and then, assuming it is not close enough, it is adjusted by what is called milling, wherein it is blended with a calculated amount of a past set aside lot of the same powder type that has its burn rate on the other side of nominal from what the new lot has.

That process makes starting load recipes safe, however, it also means some older powder is mixed with the newer powder, and powder breakdown is a snowball effect, and will happen when the older powder starts to go. This, and the fact powder is a commodity and surplus lots and other sourced lots are various ages are acquired and get used for milling, means shelf life is not readily predictable. I've had both Accurate 3100 and Vihtavuori N140 go bad within 20 years, despite basement temperature storage. I've seen recall notices on powders that were going bad prematurely, like IMR4007.

Owing to these vagaries, Norma says they guarantee their powders will last ten years after purchase, but that's as far as they are willing to go. Usually they last longer. If you are lucky enough to get some that is a single lot that didn't need milling, it should last the longest. If it's a single-base stick powder, the military will allow stockpiled ammunition that uses it to age 45 years before they rotate it out into the surplus market. If it is a double-base spherical propellant, they only give it 20 years, as these tend to break down faster. Those can all last twice as long as the military allows under the right storage conditions, but with canister grade powder you just don't know the real age of the constituents, so it is best not to load ahead too far, in my view, and if you do wind up with decades-old rounds (and I have a few), then it is best to pull a few samples and check the powder before firing it.

[Jim Watson]

Milling, huh?
In my field we called it back blending and it is a recognized method of producing uniform granular products. Hard to think of the powder company keeping old crap around for so long as to trigger a bad apple in the barrel effect.

There used to be a caveat that surplus ammo less than 3 years old was probably from production overrun and ammo more than 10 years old was out on an arbitrary age limit. But there was concern that stuff 3 - 10 years old was rejected for cause.

[The Happy kaboomer]

In climate controlled storage it will last forever plus 3 days.

[Unclenick]

Jim,

Yeah, blending was my only term, originally. I got milling from someone who is in the trade and says milling is frequently used here. I don't know why. He says folks would be astonished by some of the horse-trading and sourcing practices in the powder business. He says he's had Hodgdon folks bidding against him for the same surplus lots of powder. Where they end up, I don't know, but Hodgdon claims they don't supply manufacturers other than some very small specialty places. The bottom line is that it is difficult to know what age your powder really is, and you don’t normally have a storage condition chain of custody or history that comes with it. I think these factors explain a good number of the recall notices that have occurred in the past.

In addition to the total recall of all IMR 4007 SSC lots, there have been past lots of 4350 and N140 recalled for premature deterioration in the past. There are also less specific recalls for other powders like Accurate 2520 and Ramshot Hunter that simply warn that high pressures can occur. More premature breakdown? Wrong packaging? Bad "blending" or "milling?" here is another unfortunate situation in which pressure can be increased because the stabilizer has been consumed, and the deterrents have then been attacked faster than the powder mass, leaving you with what amounts to a reduced charge, but a reduced charge of much faster-burning powder that can raise peak pressure appreciably, while actually lowering velocity due to the loss in total gas volume.


The Happy kaboomer,

No. Smokeless powder will not last forever, even in good storage conditions. This is why the military puts time limits on stockpile storage. When smokeless powder is manufactured, it has a stabilizer chemical included in the mix. Usually, it is the antioxidant diphenylamine, though others have been used. Nitrocellulose and, in double-base powders, nitroglycerin, regularly experience the spontaneous breakdown of individual molecules on a random basis. It is the result of how heat energy distributes at the molecular level, occasionally making a momentary high temperature occur in an individual molecule that breaks it down. When that happens, nitric acid radicals (what makes the acrid smell and sometimes red vapor and red dust in a powder that has gone bad) are released. Allowed to run loose, the acid attacks other molecules, and this is what initiates the snowballing breakdown effect. The role of the stabilizer is to capture and neutralize acid radicals before enough of them accumulate to cause that problem. However, over time this constant low-level neutralizing of acids from spontaneous molecule breakdown uses up the stabilizer. Once it is gone, there is no longer a brake on powder deterioration.

While it's not often that powders go south, it just isn't never. As I mentioned earlier, I've had it happen twice. It is a good general practice whenever you open a container to waft the air from the top toward your nose for a quick sniff to check for the scent of nitric acid. The odds are you will only smell ether or other solvent odors, and those are normal. But nitric acid, while it doesn't smell exactly like vinegar, is closer to that than the solvents are. I think you'll know it when you encounter it.

[hdwhit]

Durability depends entirely upon how the components and the finished product were stored before and after reloading.

I have the unique experience of having been engaged in reloading several hundred rounds when I was suddenly stricken with Multiple Sclerosis.

Hundreds of rounds were at various stages of the reloading process when it all stopped in about 2005. I didn't get back to reloading until about 2016.

Cases stored in ziploc bags suffered severe degradation.

Cases still in the reloading blocks also fared poorly.

Cases that had been resized and stored with the residue of the resizing lubricant still on them fared better.

Cases that had been resized, tumbled to remove the lubricant and then stored in boxes where each case had its own compartment and were then stored in a 50 cal ammo can suffered only trivial damage.

PM me if you want more details, but I have .223 rounds that have been properly stored since 1980, that my Father receny took out and shot with no problems.

[Metal god]

Originally Posted by UN

It is a good general practice whenever you open a container to waft the air from the top toward your nose for a quick sniff to check for the scent of nitric acid.

I do that every time but only because I love the smell of gun powder in the morning ;-)

As to blending/milling . Do we have an estimate as to how long a manufacture would hold a lot for milling before discarding it . I would think no longer then the 10yrs they guaranty . I think that's the number we all need to know how long will they hold a lot back for milling ? . If military allows 45yrs on new bulk powder then I'd say cut that in half for canister grade powders as a most likely safe to use time period . Only because I could see a manufacture holding on to powder 20yrs for milling if expected to last 45yrs . This results in a 25yrs canister grade shelf life with a 10yrs warranty ? This is not to say 25yrs is the expected shelf life , only if milled the likely guarantied shelf life ??? It could easily last longer ????

If not obvious to some , these are not statements of facts . I'm just thinking out loud here with some questioning on the back end .

[GeauxTide]

When I started loading for a 7mm Weatherby in 1970, I used H4831 powder that was WW2 surplus. Factory ammo will last a VERY long time, unless you expose it to hot/cold extremes.

[Unclenick]

MG,

AFAIK there is no fixed number. Add in that sometimes surplus lots are part of the mix, and the uncertainty gets bigger. I suspect this accounts for the recalls for the premature deterioration that we see from time to time, though in the case of IMR4007SSC lots all being recalled (at first, it was just a few lots, and later became all), one suspects some sort of fundamental formulation error or a particular component being contaminated in some way. It is no longer in their lineup.

The military has been known to send lot samples to a lab to determine how much diphenylamine remains before loading it, illustrating that they don't always trust age and storage conditions alone to determine remaining life expectancy. Norma says that when they make a run of one of their powders, they split it up into several sub-batches and apply different amounts of deterrent to each one and then test their resulting burn rates, and then work out a blend from that information to hit their desired burn rate. This would tend to give you finished powder all the same age, except it begs the question, what do they do with leftovers from the fast and slow end of the group that doesn't make it into the finished? I assume it gets held back. How long? You'd have to write them to ask. My guess would be that each maker either sets their own limit or uses the military method of testing the remaining stabilizer content. Lots of steps mean lots of opportunities for someone to make a mistake.

And I don't mean to scare anybody unnecessarily, but having had three deterioration failures in my loading life, two bad canisters of powder, and one crate of surplus ammo all going bad just eleven years after its date of manufacture (probably the reason is was made surplus), I just don't load too far ahead anymore.

[foxmeadow]

I've got .30-06 rounds from 1944 and they go bang with acceptable accuracy for military ammo shot through a Garand..

[gwpercle]

Look at the Use By date on the box and add 100 years ...

I just went to the range and shot a box of 1943 WWII 9mm luger ammo , my Dad bought the ammo (500 rounds) and Walther P-38 in 1961 and set them on his closet shelf .
That makes the ammo 79 years old and every round fired without a hitch .
Stored on a shelf ... 100 years is not unreasonable .
Gary

[44 AMP]

Here's the thing about the mfg's "shelf life" of chemical compounds, it is ALWAYS many years (possibly even decades) less than the usual breakdown time of the product.

Improper storage, of course blows all guarantees and expectations out the airlock....

Be it paint, solvents, glues,lubricants gunpowder or anything else the people who make it have a decent idea of how long it will last and still be "good" to use, and then the guarantee their product (with proper storage) for much less time that that, sometimes only a fraction of the time,. so that none of it goes bad (and they have to spend money to replace) during its "regular shelf life".

Lots of things are like that, including mechanical things, where if something is needed to last say 30 years, its deliberately designed and built to last 100 or even 300, so they can be certain it won't fail during the "guaranteed" time period.

You powder will last until it goes bad. WHEN that will happen, no one can say. Century is certainly possible. Going bad after a decade has also happened, when it was made poorly or stored improperly.

And, it isn't always "wartime production pressure" that results in poor maufacture, either...

[reynolds357]

Depends on the powder and the storage conditions. About 10 years ago, we shot a bunch of WW2 surplus corrosive 8x57 Mauser.

[hdwhit]

I am shooting reloads that I did in 1981 & 1982, and am still getting essentially the same velocities (per the same chronograph) as I did in the 1990's.

They were all loaded with IMR-4198, IMR-3031 or Winchester 748. I can't speak to the performance of other powders.

[akinswi]

1983 great year, year I was born. Shoot it you will be fine.