A decade or so ago there was a shortage of primers in my area and I bought what I could. In fact, I bought a whole bunch, something they would now call "hoarding" I am sure. Among them was a sleeve of Rem 7 1/2 (5,000 count).

I've been having problems with a tempermental 204 Ruger with excessive SDs in load development. Yesterday's trip to the range with fresh primers eliminated the SD problem and cut group size by 50% (10 shot groups). The old primers were stored at room temperature since purchase and my assumption was that shelf life would be exteneded -- at least beyond ten years.

Today's I continued the testing with large rifle (Fed 215), old and new. While the results weren't as dramatic, the fresh primers still gave groups that were 30% smaller than the old primers, all other things equal.

Got fresh primers?

I have some large pistol primers I got several years ago,and they were old then. They are the Winchester LPs that are in the older white packaging materials. I also have 10 one pound containers of Unique that is just as old, when it was under the Hercules brand name. I've been using it to load 45 Long Colt and 45 ACP. To move the powder a little faster, I've recently started to use it in my 12 GA skeet loads in place of Clays powder. Outside of leaving my barrels dirty, all seems OK. You have to wonder how long a shelf life this stuff has.
Keep it coming...

It depends. Primers that are stored on a cool, dry place should last a long, long time. I recall the primer shortage in the early 1990s and stocked up when they were again available. Those primers seem to be just fine. I saw ammo from WWI and WWII that went off when fired. So it depends. All the best...
Gil

I have some CCI 550's and CCI 300's from the primer shortage period and they are doing just fine. All go off with a bang...Primers probably have a better shelf life then powder. Although I have a pound and a half of 2400 in the square tins (metal) that is shooting up to par with new 2400 also.

when I bought my relaoding press. it was second hand from a person I know from work.

he had some IMR3031 and some Unique powder. they was in the old tin cans. and probably a good 20 years old or more. I have used it all , and it seems to work just fine.

all the primers he had , he threw away, and did not want to give me any of them. he said they was cheap enough , and the ones he had was as old as the powder, and did not want me taking a chance of any of the primers not working, because of their age.

for testing. he did take a primer and put it in a empty shell. clamping it down in a vice. and with a hammer and punch, hit the primer.
wow, was I amazed how how loud it was. and it shot a good flame out.
as small as those things are. they do carry a good punch.
I would say, age, did not effect them at all.
my opinion, if they stay dry, they might stay workable.
I know he kept all this stuff in a barn stored up for a few , many few years. the press need some care to remove some rust. lol. but it works great.

oh, all the stuff was stored in Colorado, so it was in extreme cold and worm weather.

In 1992 I bought up (hoarded) several thousand primers of different types. Most were pistol and never had any trouble with them. The rifle primers were used up over a few years but none of them in a .204. NO problems.

My .204 has had nothing but a steady diet of new CCI BR-4s....I just like them and use them in several other project guns.

I still have a few thousand primers and several pounds of different powder left that I bought in the 90's. I keep it all in my garage which suffers temperature extremes during the year, but I don't have any problems with the powder or primers. This stuff is pretty stable and has a heck of a long shelf life. As long as my reloads are still accurate and reliable, I won't be disposing of any of it.

Yup, I wouldn't throw old powder or primers away, especially, when used in basic hunting grade rifles. In point of fact, I have never had a misfire with the older primers. OTOH, if one is striving for the finest accuracy possible, my suggestion is to try fresh primers as well as the older ones to see if there is a difference. In my cited cases, there certainly was. It manifested itself primarily in SDs and subtle to significant changes in accuracy.

At some point we stop discussing and begin testing. Your results may vary . . .

The idea that powder and primers get "too old" is common but unlikely if they are properly stored. I have some small pistol caps that were GI surplus sold in the 50s. They still work fine, as does what's left of a 50# keg of original Hogden 4831 power.

Well I have several thousand primers that are at least twenty years old .. And until my 20-30 year old powders start to smell like rotten eggs , I'll keep usin' 'em ...