Whether you're building an emergency supply, taking advantage of bulk pricing, or preserving collectible ammunition, proper long-term storage is the difference between rounds that fire perfectly after 50 years and expensive paperweights after just 5. This guide combines military storage standards with practical civilian methods to help you preserve your investment for generations.
The 4 Storage Methods: From Basic to Bulletproof
📦
Basic Box Storage
Lifespan: 5-10 years
Original packaging in a closet. Better than nothing, but vulnerable to humidity and temperature swings. Only suitable for ammo you'll use soon.
🔒
Metal Ammo Cans
Lifespan: 10-20 years
Military surplus cans with rubber gaskets. Good moisture protection if seal is intact. Add desiccants for better results.
💼
Evergreen Cases + Desiccants
Lifespan: 30-50+ years
IP67-rated Evergreen cases with moisture control. Military-spec protection that maintains perfect conditions indefinitely. Best cost-to-protection ratio.
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Vacuum Sealed + Climate Control
Lifespan: 50-100+ years
Laboratory-grade preservation. Vacuum-sealed mylar bags in temperature-controlled storage. Overkill for most, perfect for collectors.
The Science: What Actually Preserves Ammunition
Understanding why ammunition deteriorates helps you prevent it. Modern ammunition is remarkably stable when stored correctly, but four environmental factors determine whether your ammo lasts 5 years or 50:
| Factor |
Optimal Range |
Acceptable Range |
Danger Zone |
Impact on Lifespan |
| Temperature |
55-65°F |
40-85°F |
<32°F or >100°F |
10°F increase = 50% faster degradation |
| Humidity |
30-50% |
20-60% |
>70% |
Primary cause of corrosion |
| Temperature Stability |
±5°F daily |
±15°F daily |
±30°F daily |
Cycling causes condensation |
| Air Exposure |
Sealed container |
Closed container |
Open air |
Oxidation and moisture ingress |
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Military Storage Secret
The U.S. military stores ammunition at 60°F and 45% humidity. At these conditions, properly manufactured ammunition maintains 99%+ reliability for 50+ years. Lake City ammunition from the 1960s stored this way still fires perfectly today.
Step-by-Step: Setting Up 50-Year Storage
1
Inspect & Sort Your Ammunition
Check every round for corrosion, damage, or defects. Never store questionable ammo with good ammo—one bad round can accelerate deterioration of others. Sort by caliber and date of manufacture.
2
Choose Your Container System
For best results, use IP67-rated waterproof Evergreen cases. Size them for specific calibers—don't mix. Our 56-size case holds 100 rounds of 9mm perfectly, while our 230-size handles 300 rounds or mixed calibers. The airtight seal and rugged construction ensure decades of protection.
3
Add Active Moisture Control
Use 10-20 grams of silica gel per 100 rounds. Military-grade desiccant cartridges last 2-3 years. When indicator beads turn from blue to pink, recharge in oven at 200°F for 2 hours or replace.
4
Create Your Inventory System
Label each container with: caliber, quantity, manufacturer, lot number, and storage date. Keep a master spreadsheet. This prevents unnecessary opening and tracks rotation.
5
Select Your Storage Location
Interior closets on ground floors are ideal—stable temperature, low humidity. Avoid: basements (moisture), attics (heat), garages (temperature swings), and vehicles (extreme conditions).
6
Implement Rotation Protocol
Use "First In, First Out" (FIFO) system. Mark containers with colored tape by year. Shoot your oldest ammo at the range while keeping newer stock for long-term storage.
The Rotation System That Maintains Fresh Stock
📊 FIFO Rotation System
NEW PURCHASE
→
LONG-TERM STORAGE
→
RANGE/PRACTICE
New ammunition goes to back of storage, oldest ammunition moves to ready-use container
Rotation Schedule by Use Case:
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Competition Shooters: Rotate every 2-3 years for consistent performance
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Home Defense: Rotate every 5 years, test-fire old stock
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Emergency Preparedness: Rotate every 10 years minimum
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Investment/Collectible: No rotation—preserve indefinitely
Storage Location Guide: Best to Worst
✅ Ideal Locations
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Interior Closet (Ground Floor): Most stable temperature and humidity
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Under Bed Storage: Climate-controlled, accessible, hidden
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Dedicated Gun Room: Purpose-built with proper ventilation
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Climate-Controlled Storage Unit: For large collections
⚠️ Acceptable with Precautions
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Basement: Only with dehumidifier running 24/7
-
Second Floor Closet: Watch for summer heat buildup
-
Safe/Vault: Add extra desiccants, check regularly
❌ Never Store Here
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Attic: Extreme temperature swings (40°F to 140°F)
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Garage: Humidity, chemicals, temperature extremes
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Shed/Outbuilding: No climate control
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Vehicle (Long-term): Daily temperature cycles destroy ammo
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Near Water Heater/Furnace: Heat and humidity
💰 The Real Cost of Poor Storage
Let's say you have 5,000 rounds worth $2,500. Here's what poor storage really costs:
$125
Lost per year (5% degradation)
$2,500
Total loss at 10 years
$150
Cost of proper storage
Proper storage pays for itself by preserving just 6% of your ammunition.
Advanced Techniques for Maximum Preservation
Vacuum Sealing (For 50+ Year Storage)
- Place ammo in mylar bags with oxygen absorbers
- Vacuum seal using chamber sealer (not edge sealer)
- Store sealed bags in rigid containers
- Label with date and contents
- Check seal integrity annually
The "Bank Vault" Method
For irreplaceable or investment ammunition:
- Individual round sleeves
- Nitrogen-purged containers
- Temperature data logger
- Humidity monitor with alerts
- Annual inspection without opening
Bulk Storage Solutions
For 10,000+ rounds:
- Multiple waterproof cases organized by caliber
- Stackable case systems with clear labeling
- Larger format cases for bulk ammunition
- Climate-controlled room with monitoring
Special Considerations by Ammo Type
Rimfire (.22LR)
- More sensitive to moisture than centerfire
- Wax-coated bullets can melt above 100°F
- Rotate every 5 years for best reliability
- Store in smaller batches (500-1000 rounds)
Steel Case (Wolf, Tula)
- Polymer coating traps moisture—needs extra desiccant
- Inspect bi-annually for rust
- Maximum 10-year storage recommended
- Keep separate from brass ammo
Match/Competition Ammo
- Temperature stability critical for consistency
- Store in original packaging when possible
- Document velocity/accuracy before storage
- Test sample every 2 years
Defensive/Hollow Points
- Rotate every 2-3 years if carried
- Oil from handling degrades primers
- Store separately from practice ammo
- Mark rotation date clearly
Annual Maintenance Checklist
📅 Yearly Storage Inspection
✓
Check all container seals for integrity
✓
Replace or recharge desiccant packs
✓
Inspect 5% sample for corrosion or damage
✓
Update inventory spreadsheet
✓
Test fire oldest ammunition
✓
Verify storage area temperature/humidity
✓
Rotate stock according to FIFO system
✓
Clean storage area, check for pests
Start Your 50-Year Storage System
Military-grade protection that pays for itself by preserving your investment
Shop Storage Cases →
Frequently Asked Questions
Q: What's the longest ammunition has been successfully stored?
Military surplus ammunition from WWII (1940s) still functions reliably when properly stored—that's 80+ years. Civilian ammunition from the 1950s-60s stored in climate-controlled conditions regularly sells at premium prices and fires perfectly.
Q: Should I oil my ammunition for storage?
Never. Oil penetrates primer pockets and bullet crimps, deactivating primers and contaminating powder. This is one of the fastest ways to ruin ammunition. Keep all petroleum products away from stored ammo.
Q: How much desiccant do I need?
Use 10-20 grams of silica gel per 100 rounds, or one 40-gram packet per ammo can. For Evergreen cases with ARIDZONE technology, one cartridge handles up to 300 rounds. More is better than less—you can't over-dry ammunition.
Q: Is it better to store ammo loose or in boxes?
Original boxes are best—they provide cushioning, organization, and lot tracking. Loose storage saves space but increases handling damage. If storing loose, use dividers or foam to prevent rounds from banging together.
Q: Can I store different calibers together?
While possible, it's not recommended. Mixing calibers makes inventory difficult and increases the risk of chambering wrong ammunition. Dedicated containers for each caliber prevent dangerous mistakes.
Q: How do I know if my storage is working?
After one year, inspect a 5% sample. Look for: bright brass (no green corrosion), intact primers, no powder leakage, firm bullet seating. If this sample looks new, your storage system is working.
Q: What about storing primers and powder?
Primers: Same conditions as loaded ammo, maximum 10-year storage. Powder: Original containers only, rotate every 5 years, watch for color changes or acidic smell. Both degrade faster than loaded ammunition.
The Bottom Line: Time Is Money
Proper long-term ammunition storage isn't complicated—it just requires the right equipment and consistent practices. The difference between ammunition that lasts 5 years versus 50 years comes down to controlling four factors: temperature, humidity, air exposure, and handling.
Remember:
- Cool, dry, and stable beats any single perfect condition
- Moisture is enemy #1—control it aggressively
- Quality Evergreen cases pay for themselves quickly
- Rotation keeps your ready supply fresh
- Annual inspection prevents surprises
Whether you're storing 500 rounds or 50,000, these principles scale. Start with proper Evergreen containers and moisture control—everything else is optimization.
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Investment Perspective
At current inflation rates, ammunition purchased today and properly stored for 20 years effectively earns a 3-5% annual return just from price appreciation—tax-free. Add in availability during shortages, and long-term storage becomes one of the smartest investments shooters can make.
Disclaimer: This guide provides general information based on industry best practices and military storage standards. Storage results may vary based on ammunition quality, environmental conditions, and maintenance. Always follow manufacturer recommendations and local regulations for ammunition storage.
About This Guide: Created by Evergreen Cases based on military specifications, industry standards, and decades of combined storage experience. For specific storage solutions, visit our complete ammunition case collection.
