Does Ammo Expire? How Long Ammunition Lasts
Most boxes of ammunition don't have an expiration date printed on them, which leaves many shooters wondering if old ammo is still safe and reliable. Here's the practical answer.
The short answer
Modern factory ammunition doesn't expire the way food does. Stored in a cool, dry place, it can stay reliable for many years, and people regularly shoot ammunition that is decades old without problems. Manufacturers often quote a shelf life of around ten years, but that's generally a conservative figure, not a point where ammo suddenly stops working.
What really determines how long ammo lasts is how it was stored, not the calendar.
What makes ammo go bad
- **Moisture and humidity.** This is the biggest factor. Water causes corrosion on the case and can get into the primer or powder, causing misfires or weak ignition.
- **Heat.** High temperatures and repeated heating and cooling can slowly degrade powder and primers.
- **Oil and solvents.** Gun oil or cleaning chemicals can seep into a case and ruin the primer or powder.
- **Physical damage.** Dented cases, loose bullets, and rough handling can cause feeding problems or unsafe pressures.
Signs that ammo may be bad
Look at your ammo before you shoot it, especially if it's old or you're not sure how it was stored.
- Green, white, or heavy tarnish on the case
- Dents, cracks, or a bullet that moves in the case
- Visible powder leaking out
- Oily or sticky rounds
- A rattling or odd sound when you shake a round
If you see any of these, don't shoot it. Misfires, hangfires, and squibs can damage a firearm and hurt the shooter.
Does the type matter?
Storage matters more than type, but a few notes apply:
- Centerfire ammunition in sealed brass cases tends to hold up very well.
- Shotgun shells with paper or lower-quality hulls are more sensitive to humidity than plastic hulls.
- Military surplus ammunition may be corrosive, meaning the primer residue can damage a barrel if you don't clean it promptly.
- Handloaded ammunition is only as reliable as its components and how it was assembled and stored.
What to do with ammo you don't trust
Never throw live ammunition in the trash or burn it. Contact a local range, a licensed dealer, or your local authorities and ask about safe disposal options.
How to make ammo last
Keep it cool, dry, and sealed in a good container with a desiccant pack. Rotate your stock so older boxes get used first, and check your containers a few times a year. Our guide to storing ammo covers each step in detail.
Tracking age and lot numbers
When you know when you bought a box and what lot it came from, you can shoot your oldest ammo first and spot problems if a manufacturer issues a recall. Ammo Box records the date you added each box, and lets you add a lot number and an optional expiration date if one is printed on the packaging.