The standard .50 cal ammo can (M2A1) measures 11.7 inches long, 6.0 inches wide, and 7.5 inches tall. But that’s just one of five standard military sizes. From the slim 30 cal that slides under a truck seat to the massive 20mm heavy that holds 1,500 rounds, every size has exact specs that affect stacking, storage, and what actually fits inside.
Ammo Can Dimensions Chart
Keep this chart handy for storage planning, shelf builds, gun safe layouts, or bulk ammo purchases.
Ammo Can Dimensions Chart
| Can Type | Exterior (L × W × H) | Interior (L × W × H) | Empty Weight | Typical Capacity |
|---|---|---|---|---|
| .30 Cal (M19A1) | 11″ × 3.7″ × 7.25″ | 10″ × 3.5″ × 6.5″ | ~4–5 lbs | 500–600 loose 5.56 / 1,000+ 9mm |
| .50 Cal (M2A1) | 11.7″ × 6.0″ × 7.5″ | 11.0″ × 5.6″ × 6.9″ | ~5.8–6.2 lbs | 800–1,000 rds .308 |
| Fat .50 (PA-108) | 12″ × 7.5″ × 9″ | 11″ × 7″ × 8.5″ | ~7 lbs | 25–30% more than standard .50 |
| 40mm (PA-120 / M548) | 17.5″ × 6.1″ × 9.5″ | 16.8″ × 5.5″ × 8.0″ | ~12–14 lbs | 32 linked 40mm grenades |
| 20mm Heavy | ~25″ × 12″ × 15″ | ~24″ × 11″ × 14″ | 25–30 lbs | Up to 1,500 rds 7.62 or 5.56 |
All genuine U.S. military ammo cans are built from 0.9–1.2mm (20-gauge) steel and carry a stamped NSN (National Stock Number) — the only reliable proof of authentic military-spec construction. Cheap import cans drop to 0.6mm and fail the seal test within months.
Standard Ammo Can Dimensions by Size
Every size has a specific job. Here’s exactly what each one measures — and what that means in real use.
.30 Cal Ammo Can Dimensions (M19A1)
The .30 cal ammo can stands 7.25 inches tall, 11 inches long, and only 3.7 inches wide. Interior usable space measures 10″ × 3.5″ × 6.5″. Empty weight is 4–5 lbs.
That 3.7-inch width is the defining number. It’s the only standard ammo can slim enough to slide under most U.S. truck and SUV bench seats without modification.
.50 Cal Ammo Can Dimensions (M2A1)
The .50 cal ammo can is 7.5 inches tall, 11.7 inches long, and 6.0 inches wide. Interior space is 11.0″ × 5.6″ × 6.9″. Empty weight runs 5.8–6.2 lbs.
This is the most popular military surplus storage can in the United States — and for good reason. That extra width and height over the .30 cal swallows bulk ammo without a rattle.
M2A1 vs M2A2: Both share the same external footprint. The M2A2 added a reinforced hinge. Either works identically for storage. NSN: 8140-00-828-2938.
Fat .50 Cal Ammo Can Dimensions (PA-108)
The Fat 50 ammo can measures 9 inches tall, 12 inches long, and 7.5 inches wide. Interior dimensions are 11″ × 7″ × 8.5″. Empty weight is approximately 7 lbs.
That extra 1.5 inches of width and 1.5 inches of height over the standard M2A1 translate to 25–30% more internal volume. Most shooters don’t realize this is a completely different can — not just a bigger .50 cal.
40mm Ammo Can Dimensions (PA-120 / M548)
The 40mm ammo can is 9.5 inches tall, 17.5 inches long, and 6.1 inches wide. Interior usable space reaches 16.8″ × 5.5″ × 8.0″. Empty weight is 12–14 lbs.
That 16.8 inches of interior length is the standout spec. No other standard ammo can comes close.
20mm Heavy Ammo Can Dimensions
The 20mm ammo can is the largest standard military surplus size. It measures approximately 15 inches tall, 25 inches long, and 12 inches wide. Interior space is roughly 24″ × 11″ × 14″. Empty weight hits 25–30 lbs.
Round capacity: Up to 1,500 rounds of 7.62 or 5.56. Two side-mounted handles make carrying manageable despite the weight.
Ammo Can Exterior vs. Interior Dimensions Compared
Exterior size tells you if it fits in your storage space. Interior size tells you what actually fits inside. Both numbers matter.
Ammo Can Exterior vs. Interior Dimensions Compared
| Can Type | Exterior L (in) | Interior L (in) | Exterior W (in) | Interior W (in) | Exterior H (in) | Interior H (in) |
|---|---|---|---|---|---|---|
| .30 Cal (M19A1) | 11.0 | 10.0 | 3.7 | 3.5 | 7.25 | 6.5 |
| .50 Cal (M2A1) | 11.7 | 11.0 | 6.0 | 5.6 | 7.5 | 6.9 |
| Fat .50 (PA-108) | 12.0 | 11.0 | 7.5 | 7.0 | 9.0 | 8.5 |
| 40mm (PA-120) | 17.5 | 16.8 | 6.1 | 5.5 | 9.5 | 8.0 |
| 20mm Heavy | ~25.0 | ~24.0 | ~12.0 | ~11.0 | ~15.0 | ~14.0 |
Key takeaway: The gap between exterior and interior is consistent — roughly 0.5–0.9 inches on each dimension. That gap is the steel wall, hinge recess, and gasket seat combined. Always plan your foam inserts and ammo box stacking against interior numbers, not exterior.
Question’s
What are the dimensions of a standard ammo can?
The standard military ammo can is the .50 cal (M2A1): exterior 11.7″ × 6.0″ × 7.5″, interior 11.0″ × 5.6″ × 6.9″, empty weight 5.8–6.2 lbs. It is the most widely used surplus can in the USA.
What are the inside dimensions of a 30 cal ammo can?
The interior of a .30 cal (M19A1) measures 10″ × 3.5″ × 6.5″. That space fits 500–600 loose rounds of 5.56 or over 1,000 rounds of 9mm.
How tall is a 50 cal ammo can?
A standard .50 cal ammo can (M2A1) stands 7.5 inches tall (exterior). The Fat .50 (PA-108) is taller at 9 inches. Both hold different capacities — the Fat 50 stores 25–30% more.
What is the difference between a Fat 50 and a regular 50 cal ammo can?
The Fat 50 (PA-108) is wider (7.5″ vs 6.0″) and taller (9″ vs 7.5″), giving 25–30% more interior volume. It was designed for linked belt ammo where the standard M2A1 is too narrow to work properly.
How thick is the steel on a military ammo can?
Authentic U.S. military ammo cans use 0.9–1.2mm steel — approximately 20-gauge. Cheap import cans drop to 0.6mm, dent on light impact, and lose their airtight seal quickly.
What ammo can fits under a truck seat?
Only the .30 cal (M19A1) at 11″ × 3.7″ × 7.25″ is slim enough to slide under most standard U.S. truck and SUV bench seats.
How many rounds of 9mm fit in a 30 cal ammo can?
A .30 cal can holds approximately 1,000–1,200 rounds of 9mm loose. Keeping ammo in factory boxes drops that to 800–1,000 rounds depending on box configuration.
What is an NSN on an ammo can?
NSN stands for National Stock Number — a stamped military identification code that proves a can meets authentic U.S. military specifications. Each can type has its own NSN. The .50 cal M2A1 carries NSN 8140-00-828-2938.
Are ammo can dimensions the same across all manufacturers?
Not exactly. Minor variations of 0.1–0.2 inches exist between manufacturers, especially in older surplus stock. Core specs follow U.S. military MIL-SPEC standards, but always measure interior dimensions before cutting foam inserts or ordering custom organizers.
What is the largest standard military ammo can?
The 20mm heavy ammo can at approximately 25″ × 12″ × 15″ exterior. It holds up to 1,500 rounds of 7.62 or 5.56 and weighs 25–30 lbs empty. It is the least common but most capacious standard surplus can available.
Sara Khan is the admin of Suitcases Size. She manages website content, reviews measurement guides, and ensures readers get simple, accurate, and easy-to-understand information about sizes, dimensions, and travel measurements.