The enemy is water, and cardboard is a sponge
Ammunition is surprisingly durable. Kept cool and dry, factory ammo can stay serviceable for a very long time. Kept in a damp garage in its original cardboard, it starts a slow fight with humidity that it eventually loses: corroded cases, tarnished bullets and, in bad cases, primers that misbehave.
Most of the work of preserving a stockpile is boring: put it in a sealed container, keep the room stable, and know what you have. This guide covers the gear that does that best for people who buy ammo by the case. Our existing guide on how to store a case of ammo covers temperature and humidity in more depth; this one is about the hardware.
We have not tested these products. Specs come from the listings and manufacturer descriptions shown on Ammunition Depot.
Best overall: M2A1 .50-cal steel can
The M2A1 is the shape everyone pictures when they hear "ammo can," and for good reason. It was designed around belted .50-caliber ammunition, and its lid closes on a gasket that keeps moisture out. The version at Ammunition Depot is described as newly made and never used, steel, with a gasket-sealed lid. Exterior dimensions are listed at 11.75 by 6 by 7.5 inches.
Why it wins for bulk storage: steel is crush-resistant, the gasket seals well, the rectangular shape stacks efficiently on shelves, and a new can avoids the hardened gaskets and dents common on old surplus.
The trade-off is weight. Steel cans are heavy before you add ammunition, and a full one is a real lift. Use it for stock that stays on a shelf, not for carrying across a parking lot.
Best smaller steel can: M19A1 .30-cal
The M19A1 is the narrower sibling, built for ammunition up to .30 caliber. Ammunition Depot's new version is cold-rolled steel with a powder-coated olive finish and a gasket-sealed lid, with interior dimensions of 3.5 by 10.125 by 6.75 inches and an empty weight of 3.75 pounds.
It is the better choice when you want manageable weight per can, a separate can for each load, or a box you can carry one-handed. Pistol calibers in particular get heavy fast, so a .30-cal can full of 9mm is easier on your back than a fully packed .50-cal.
Best polymer can: MTM AC50C 50-cal
MTM's AC50C is the plastic answer to the M2A1. Ammunition Depot's listing describes polypropylene construction that will not rust, a tongue-and-groove O-ring seal, double padlock tabs and molded stacking ridges, with a weight capacity of 25 pounds and dimensions of 7.4 by 13.5 by 8.5 inches.
Polymer cans shine where steel is annoying: they are lighter, quieter, will not rust in a damp basement, and the padlock tabs are a useful layer of access control. The honest limitation is that MTM rates its cans water-resistant, not submersible. For a dry room, that distinction barely matters. For a flood-prone basement, steel or a sealed dry box is the stronger choice.
Also consider: MTM's tall AC30T .30-cal can, rated at 15 pounds, and the Case-Gard mini, which MTM says holds up to 700 rounds of 9mm or 400 of .45 ACP or .223 with a 12-pound carry capacity. The mini is a smart size for a single range session's worth of loose rounds.
Best for overflow: a large O-ring dry box
When a case or two outgrows your cans, a larger sealed box keeps the overflow together. MTM's Sportsmen's Plus Spud 7 is listed at 18.5 by 13 by 15.25 inches, polypropylene, with a water-resistant O-ring seal, padlock tabs and a lift-out tray. It is big enough to hold several boxed cases, or a mix of ammo, cleaning gear and range accessories.
A big box is convenient but has one downside: it gets very heavy when full of ammunition. Put it where it will live before you fill it.
Best for transport: Pelican V250 Vault
If ammo travels with you, a crushproof case earns its premium. Pelican's V250 Vault is listed with a high-impact polyethylene shell, a polymer O-ring, two stainless lock hasps and an interior of 12.7 by 6.3 by 10 inches, with an empty weight of 5.23 pounds. The listing calls it weather resistant, without an IP rating.
For a shelf that never moves, this is more case than you need. For a vehicle or a trip to a match, it is a sturdier choice than a standard can.
Best organizer: MTM ACO can trays
The MTM ACO turns a 50-cal can into a 22-compartment organizer with three stacking trays. It is not for bulk rounds, but it is excellent for the bits that end up loose in a range bag: ear plugs, small parts, chamber flags, a few boxes of a specialty load. The can is sold separately.
Desiccant: the smallest upgrade with the biggest payoff
A sealed can traps whatever air was inside when you closed it. On a humid day, that air carries moisture. A silica-gel desiccant pack inside the can soaks it up.
Ammunition Depot's ammo can category did not list standalone desiccant when this was written, though its FAQ recommends silica gel. MTM's Survivor bucket-style can comes with a vapor corrosion inhibitor bag and a desiccant pack. Otherwise, rechargeable silica-gel canisters or packets from any general retailer work fine.
Practical tips:
- One pack per can is plenty for a dry room; add more in humid climates.
- Indicating silica gel changes color as it saturates, which makes checking easy.
- Recharge or replace packs on a schedule, such as when you rotate stock.
Labels: the gear nobody buys but everyone needs
Five identical green cans are useless if you do not know what is inside. A label on every container should show:
- Caliber and load (bullet weight and type)
- Brand and lot number, from the factory box
- Round count
- Purchase date
Masking tape and a permanent marker work. A label maker is neater. The key habit is updating it when you take rounds out. Our post on responsible storage records goes deeper on keeping track of what you have.
Crates and stackers
Wooden crates and big plastic totes are tempting for bulk storage, but most do not seal. Use them as outer containers that hold sealed cans, not as the primary barrier against humidity. A sturdy shelf rated for the weight does the same job and keeps cans off a damp floor.
The quick build
| Need | Pick |
|---|---|
| Long-term shelf stock | New M2A1 .50-cal steel cans |
| Lighter, rust-free, lockable | MTM AC50C polymer cans |
| One load per can, easy carry | M19A1 .30-cal cans |
| Overflow of boxed cases | MTM Spud 7 dry box |
| Ammo that travels | Pelican V250 Vault |
| Moisture control | Silica-gel desiccant in every can |
| Knowing what you have | A label with caliber, lot, count and date |
Prefer to buy ammo and can together? Ammunition Depot's ammo can bundles pack popular loads straight into a can; whether they are worth it is a cost-per-round question covered in our ammo can combos piece. The full container lineup is in the ammo cans category.
Editorial note: This is an independent editorial overview built from manufacturer specifications, retailer listings and published sources. We have not performed hands-on testing of the products discussed, and nothing here is a performance guarantee. Verify specifications, compatibility and the law where you live.
Frequently asked questions
Are plastic ammo cans as good as steel ones?
For indoor storage, polymer cans with an O-ring seal, such as MTM's 50-cal can, are lighter and will not rust, but MTM rates them water-resistant rather than submersible. Gasketed steel M2A1 cans are heavier and tougher. Either works in a cool, dry room.
How many rounds of 9mm fit in an ammo can?
It depends on the can and whether rounds stay boxed. MTM says its mini Case-Gard can holds up to 700 rounds of 9mm loose. Larger 50-cal cans hold more, but avoid overloading: MTM rates its AC50C can at 25 pounds.
Should I put desiccant in my ammo cans?
Yes, if the can is sealed. A silica-gel pack absorbs moisture trapped when you close the lid. Check or recharge packs periodically, especially in humid climates.
Should I keep ammo in the original boxes inside the can?
Keeping factory boxes preserves the load and lot information printed on them. Loose storage fits more rounds. A good compromise is to cut the label panel from the box and drop it in the can.
Sources and further reading
Related reading
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