Shelf Life of Shotgun Ammunition?

[Vitaly]

Received several interesting comments to my Shelf Life of Shotgun Ammunition post.

Sync suggested to start thread here, so we can discuss this.

I always thought that rifle and handgun ammo has longer shelf life because components (especially powder inside of the metal case) are protected from air and humidity. There’s no gap between bullet and shell, so the air and humidity cannot get inside of the shell.

Your thoughts?

[EdwardE]

I recently used up some 12 gauge Winchester that had been residing in one of my hunting vests hanging in the closet. Those shells were at least 10 years old. The brass was heavily tarnished but they cycled and ignited just fine.

[mercman]

I just fired two boxes of paper SG shells from the 60's. All went bang, but a few didn't seem to have the same recoil as the rest of the lot. If shells are stored in a cool, dry place and exhibit no signs of swelling or corrosion they should be fine.

[Kentactic]

I fired a couple hundred nasty looking paper shells a few months ago, from who knows when. They all went bang.

[Synchronizor]

Like I said over on the blog, shotshell energetic components (powders and primers) are very similar to what's used in metallic pistol cartridges. Many powders can be used in both shotshells and pistol cartridges, and some shotgun shells use standard pistol primers. Stored properly in a dry environment, there’s no reason shotshells shouldn't have the same shelf life as handgun ammo.

Even when stored improperly, shotshells can be pretty resilient. Quality shotshells will feature things like moisture resistant hulls (plastic, metal, or treated cardboard), sealed crimps, and/or sealed primer pockets to protect the energetic components from moisture. Even lower-quality ammo can surprise you. I’ve come across unsealed plastic- and paper-hulled shotshells that spent decades in non-climate-controlled attics and garages, and every single one cycled perfectly, went bang, and thumped my shoulder nice and hard (harder than a lot of modern loads, actually).

Metallic cartridges are vulnerable to moisture too. Like quality shotshells, premium rifle and pistol ammo often have features such as plated or lacquered cases, and sealed primer pockets to extend shelf life in less-than-ideal environments. Given the chance, water can penetrate crimps and primer pockets, or corrode brass and steel cases badly enough to interfere with function (something shotguns are far more tolerant of). Also, squib loads are much more of a concern with rifles and pistols than with shotguns. A metallic cartridge that didn't age well can result in an obstructed barrel, while shotguns, which run at lower pressures and have far less friction between the projectile and barrel, are more likely to just lose a chunk of muzzle velocity. Even if you do get a squib load in a shotgun, it's a lot easier to clear the barrel than if the same thing happened in a rifle or handgun.

Put a box of shotshells on a shelf next to a box of pistol rounds, and it'd be hard to say which would go bad first. You could argue that metallic cartridges have an advantage in a general sense, but it all depends on the environment, the quality of the ammo, and other factors. Personally, I think I'd be a lot more hesitant and careful about shooting old rifle or pistol ammo than old shotshells.

Sealed crimp on a Remington 12ga buckshot shell

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Nickle-plated case & sealed primer pocket on a Remington handgun round

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[keith44]

I stopped shooting Trap about 17 years ago (moved to where traveling to a shoot was just out of the question). When I quit shooting I had 5 cases of shells loaded up, that went into a closet. We've moved twice since then and always have kept those handloads either in a closet or in my loading room.

Today there was an unusually large flock of Starlings came into gun range...

I loaded those old rounds into the old skeet gun (just for some fun) and they shot just fine...I scored 8 out of 10 at ranges out to 35 yards.

Properly stored there are no issues with keeping shotshells for long periods of time. Your idea about an air gap has a flaw. The one piece wad / shotcup assembly seals the powder very effectively inside the plastic hull. I do have a box of paper hull 16 gauge shells that are from the 1960's that also shoot just fine (or did several years ago) since they have also been kept from getting wet.