How much larger should an ammunition container be than its contents?

Answer: 3 to 5 mm per side plus 10 to 15 mm headroom. Tighter scrapes; looser shifts.

Does a thicker wall always stack better?

Answer: Only to a point. Past 8 mm, rotomoulded walls trap unfused bubbles and a drop cracks there.

Does the relief valve let water in?

Answer: It stays sealed until 35 kPa and reseats after. Rain is excluded, but the case must not sit immersed.

Are more latches always safer?

Answer: No. Wide spacing lets the lid lift; tight spacing wears the seal flat. Four at 225 mm centres suits a 900 mm body.

What paperwork does an export order need?

Answer: UN mark test reports, drop and stack records, and a salt spray report on the hardware.

How to Choose an Ammunition Container: Five Criteria

Quick answer: Choosing an ammunition container means turning the job into five measurable criteria: interior size and dividers, wall thickness against stack height, sealing and pressure relief, latches and seal holes, handling and certification. Work them in that order and the quotation finally matches the job.

Five Criteria That Decide an Ammunition Container Spec
Setting Interior Dimensions and Dividers
Wall Thickness and Stack Height
Sealing Class and Pressure Relief
Latches, Seal Holes and Handling
FAQ

1. Five Criteria That Decide an Ammunition Container Spec

An ammunition container spec is written from the job outward, not the catalogue inward. Interior size fixes the format, wall thickness fixes the load, sealing fixes storage life, latches fix inspection, handling and certification fix movement. Get the order wrong and every later choice is a guess.

One buyer chose on unit price. At loading, the rack opening measured 1450 mm against a 1520 mm case height, so the order became a side-opening variant and delivery slipped six weeks.

Criterion	Weight	Pass line	Verify by
Interior and dividers	25	Cell clearance 3 mm or less	Trial load
Wall and stacking	20	No set at four high, 72 hours	Stack test
Sealing and relief	20	Under 5 kPa drop in 10 min	Pressure bench
Latches and seal holes	20	400 N pull per latch	Pull gauge
Handling and certification	15	90 kg static on handle	Hanging load

Shift weights per project: long-term storage lifts sealing and stacking, field use lifts handling. Above 75 earns a sample.

2. Setting Interior Dimensions and Dividers

Interior space is not the outside size minus two walls; ribs, corner bosses and the lid recess all take a bite. A 600×400×250 mm body with 4.5 mm walls gives 586×386×232 mm inside, height losing most because the lid carries seal compression.

Dividers follow the item layout. Twelve cells at 88×88×200 mm, with 4 mm plates and 1.5 mm clearance, suit uniform items; a raised rim or lifting loop needs 3 mm or it scrapes. Slotted plates beat moulded cells when the item mix changes.

3. Wall Thickness and Stack Height

Derive the wall of an ammunition container from the stack. A 600×400 mm footprint at 45 kg loaded, stacked four high, puts 135 kg on the bottom lid. Over a 400 mm span, 4.5 mm walls on a rib grid hold deflection to 1.2 mm; 3.8 mm gives 2.4 mm and the next case will not seat.

Thermoplastics creep: 72 hours at 23 °C sets about 1.6 times as much as 8 hours, so a one-hour press proves nothing. At 35 °C a four-high stack deflects 40 percent more; at minus 20 °C it deflects less but cracks instead.

4. Sealing Class and Pressure Relief

Sealing needs two numbers, differential and leak rate, not the word waterproof. Store-room duty runs 30 kPa for 10 minutes with no more than 5 kPa drop; humidity-sensitive contents need 2 kPa plus a 20 g sieve pack.

EPDM returns best near 25 percent compression and sets permanently past 40, when the second closure fails. Corners leak first, so the groove must be spliced rather than butted.

A relief valve is not an accessory. A 60 litre ammunition container cooling to minus 20 °C can lose over 15 kPa and hold the lid shut, so fit a valve opening at 35 kPa and reseating at 25 kPa, port down or capped.

5. Latches, Seal Holes and Handling

Latch count follows length: two below 600 mm, three to 900 mm, four above, the middle one on the handle axis. Specify 400 N static pull, not the usual 300 N, since a compressed lid needs more.

Seal holes sit where the latch base overlaps the body boss, 6.5 mm across for a 2.5 mm wire seal. Half a millimetre off and the wire will not pass.

Check	Basis	Acceptance
Air freight	15 kPa differential	10 min, no leak
Sea export	UN mark, 4H series	Not below packing category
Road	1.2 m drop, six faces	No crack, latch closed
Storage	Four high, 30 days	2 mm deflection or less
Hardware	240 h salt spray	No red rust

Handling hardware is forgotten most often: 90 kg static and 45 kg dynamic on the handle, two 50 mm webbing loops to spread forklift pull, and castors above 40 kg.

Conclusion

Choosing an ammunition container runs in a fixed order: interior against contents, wall against stack height, seal against storage duration, latch against inspection, handling against site equipment. Each has a measurable pass line, and in a scorecard the decision stops being a price argument. Follow the five and the specification of an ammunition container has something to stand on.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.