What is the shelf life for pistol ammunition?

Answer 1

If stored in a cool dry environment free of corrosive chemicals, pistol ammo can last pretty much indefinitely. I've heard of people using ammunition that was close to 100 years old.

2. Yes.

But in time it is found that the burn rate of the smokeless powder increases slightly, making the powder burn faster and the pressure generated inside the cartridge a little higher. Usually this has little effect on reliability or accuracy.

If the cartridge primer is exposed to moisture, or oil especially, it can deteriorate and not ignite, causing a misfire.

That said, most center fire cartridges will fire if under 50 years old.

Caliber .22 rimfire ammunition is another story as it uses a different ignition system.

Rimfire ammunition is especially susceptible to aging and may or may not fire after 15 years or so. One box of ammunition may be perfectly reliable while another may be mostly duds. This is unpredictable and depends upon the manufacturer and the ammunition brand.