MTM AC50C vs USGI M2A2 Steel Ammo Can: Which One Actually Wins for Long-Term 5.56 Storage

The Can You Choose Determines How Long Your Ammo Lasts

Most AR-15 owners default to USGI M2A2 surplus steel cans — they look bombproof, they're cheap at gun shows, and the military uses them. But for a modern civilian storage system, that logic breaks down fast. The MTM AC50C is lighter, cheaper, seals better, and costs less. Here's the full comparison.

The Full Spec Comparison

Price: You Pay More for Less with the M2A2

A Grade 1 USGI M2A2 surplus can runs approximately $22.49. The MTM AC50C runs approximately $15 new. You're paying 50% more for a used can of unknown age with a potentially degraded gasket.

The M2A2 argument is that mil-spec steel is more durable. That's true — but durable for what? You're storing ammunition in a climate-controlled space, not dragging it through a combat zone. The AC50C's polymer construction is more than adequate for the actual use case, and it seals better out of the box than a 20-year-old surplus can.

Weight: 5.9 lbs Lighter Per Can at Equal Round Count

The M2A2 weighs approximately 5 lbs empty. The AC50C weighs approximately 1.5 lbs empty. Load both with 1,200 rounds of 5.56 on 120 stripper clips and the weight difference becomes concrete:

That's 5.9 lbs per can. At 10 cans that's 59 lbs of unnecessary weight — same round count, same shelf space. If you ever need to move your storage, that difference is felt immediately.

The Seal Problem with Surplus M2A2 Cans

This is the argument surplus can dealers don't want you thinking about. The USGI M2A2's airtight seal depends entirely on its rubber gasket. On a new can, that gasket is supple and seals reliably. On a 20–40 year old surplus can, that gasket has been compressed, dried out, and potentially cracked.

Even Grade 1 surplus cans have aged gaskets. "Like new" cosmetically does not mean the gasket seals like new. A compromised gasket means humidity enters the can — and humidity is the one variable that degrades ammunition over time.

Round Capacity: AC50C Holds More

The MTM AC50C's internal dimensions are optimized for stacking stripper clips in aligned rows. On SCUSA polymer stripper clips, it holds approximately 1,400 rounds of 5.56. The USGI M2A2's internal dimensions are designed for loose rounds or bandolier packs — on stripper clips, you get approximately 1,200 rounds.

That's 200 extra rounds per can in the AC50C — at a lower price, with less weight, and with a better seal.

When Does the M2A2 Win?

To be fair: the M2A2 wins in one scenario — extreme physical abuse. If you're throwing cans off your truck to the ground, air-dropping them on pallets in a war zone, or dragging them through a combat zone, the steel construction is genuinely tougher. For a civilian storage shelf, that advantage is completely irrelevant.

It also wins for nostalgia and aesthetics. If you want the mil-spec look, the M2A2 delivers that. But nostalgia doesn't keep your gasket sealed — and a war zone is not your garage.

The Complete Long-Term Storage System

The AC50C is one component of the complete SCUSA storage system. Paired with SCUSA polymer stripper clips and Desiccare desiccant packs, it creates a sealed, color-coded, corrosion-proof storage system that outperforms any surplus steel setup on every measurable axis.

Frequently Asked Questions

Can I use USGI M2A2 cans with SCUSA stripper clips?

Yes — SCUSA polymer stripper clips work in any ammo container. The MTM AC50C is recommended because its internal dimensions are optimized for stacking loaded clips in aligned rows, maximizing round count per can. The M2A2 works but holds approximately 200 fewer rounds per can on stripper clips.

Are surplus M2A2 cans still airtight?

Some are, some aren't. It depends entirely on the age and condition of the rubber gasket. Grade 1 surplus cans are the most likely to still seal well, but even these have aged gaskets. Always inspect the gasket before trusting a surplus can for long-term storage — press it firmly and check for cracking or permanent compression.

What is the MTM AC50C made of?

The MTM AC50C is made of high-density polyethylene (HDPE) with a polypropylene latch. The gasket is a new O-ring seal. It is not made of steel and is not mil-spec — it is a purpose-built civilian ammunition storage container that outperforms surplus steel cans for civilian long-term storage use cases.

How many 5.56 rounds fit in an MTM AC50C on stripper clips?

Approximately 1,400 rounds of 5.56 NATO / .223 Remington on standard 10-round stripper clips. That's approximately 140 loaded clips stacked in aligned rows. Loose rounds fit approximately 1,000 — loading on stripper clips gives you 40% more rounds in the same container.

Does the MTM AC50C float?

What about steel ammo cans for .50 BMG or larger calibers?

This article covers 5.56 / .223 storage specifically. For .50 BMG, 7.62x51, or larger calibers, USGI steel cans in the appropriate size remain a strong option. SCUSA's system is designed specifically for 5.56 / .223 ammunition.