Steel vs. Brass Ammo: Myths Busted for Better Firearm Use

Steel vs. brass ammo has been debated in the shooting community for decades. Just like how some debate the best quarterback in football history, Joe Montana or Tom Brady, others debate the best carry round, 9mm or .45.

I may have started something here.

I’m afraid that comparing steel to brass-cased ammo is more complicated than both of those. Each casing has its pros and cons, and that’s what we will discuss in this article.

So without further ado, and so I can keep the word count for this article under 1,600 words, let’s get into it.

Brass Casing (Brief Summary)

Brass shell casings have been around since the 1870s, when it was meant to replace paper casings. Since brass was more expensive and metalworking hadn’t been perfected yet, it took a while to catch on.

Now, brass casings are the most common of the modern sporting cartridges. With brass being softer than steel, brass casings can easily take the form of the chamber that they are in. This creates a better seal, which aids in reliability and function.

The downside of brass casings is the price, especially when compared to steel. If you ever wondered why the old guy or lady at the range asks if they can pick up your shell casings, now you know.

But, since brass can be reloaded, it has the potential to be more economical in the long run.

Steel Casing (Brief Summary)

On the other hand, steel casings have been around since the 1930s/1940s. Allied and Axis forces had to move over to steel due to the shortage of materials, in this case, brass, in the world due to the war.  

So steel casings became more commonplace on the battlefield, especially for 9mm ammo.

More commonly now, you’ll see steel casings used in 7.62×39 cartridges. This is where things get interesting.

Most negative feedback against steel casings is due to the general unreliability of Russian and Chinese surplus ammo that has been sitting in ammo cans since WWII in some cases. That surplus ammo usually has Berdan primers, which are more corrosive and toxic than my last relationship.

Modern steel cartridges, like those seen from Tula and Wolf, are coated with polymer rather than the old stuff coated with lacquer. This makes it smoother and more resistant to the stuff that usually plagues steel-cased ammo.

But is it better than brass? It depends on the firearm.

I’ll pass.

Aside from the obvious differences in material, we will talk about some of the other key differences between steel and brass casings. Some of this stuff may tie together.

Reliability

Again, this is where things get tricky. While the AK-47 is one of the most combat-proven platforms of all time, it excels with steel-cased ammo in terms of reliability and overall longevity.

Over the years, the AK has withstood the test of time with all that corrosive ammo.

Alternatively, if you take steel-cased ammo and run it in an Armalite-styled firearm, you can expect some stoppages and one dirty firearm. Once you compare piston-driven vs. direct impingement firearms, this is where you start to see the reasoning.

But we’ll talk more about that in a minute.

Generally, brass is more reliable than steel casing. And it all has to do with…malleability.

What Is Malleability?

By definition, malleability is the quality that allows one piece to be shaped into something else without breaking.

Steel is one of the hardest metals in the world. It doesn’t bend or contour well. Conversely, brass will contour to the environment it is put into…like your rifle’s chamber.

The bolt face seals around brass cartridges better than steel, which is especially useful in the extraction stage of the cycle. The extractor can grip around the rim of the brass cartridge since brass seats into the bolt face easier.

That results in two things: a cleaner and more reliable firearm.

When a round is fired, the brass casing expands better to seal the chamber, lowering the amount of carbon going back into your chamber and bolt carrier group.

More pressure is directed out through the barrel and into the gas block. That higher pressure also helps your rifle function better.

Steel does not expand either, so much of those propellants go back into the system and foul up the firearm quicker than normal. You’ll find yourself having to clean firearms more frequently if steel ammo has been run through them.

It’s not fun.

What Does The Manufacturer Recommend?

When the Armalite platform was being developed, the 5.56×45 cartridge used a brass casing. And while there have been many advancements in the AR-15 platform, it has always been designed to work best with brass casings.

But what about the AK-47?

Do you remember when I mentioned the material shortage that turned countries from brass to steel casings a minute ago? Guess what Russia didn’t have an abundance of in 1947? Brass.

But they had a hell of a lot of steel ammo. So when the AK platform was built, it was designed to work best with steel ammo. It’s not to say that AK pattern rifles won’t function with brass; they do well with brass, but AR-15s aren’t as forgiving.

To this day, whenever I receive a new firearm, I always try to find out what that firearm was tested with. The manufacturer will either note it in the owner’s manual, or you can call if it’s not listed. Regardless, I believe you should find out.

Sure, you can run what you want, but I’ve had a FAL damn-near rip off the rim of a brass casing. I’ve seen it happen with older AK-47s as well. These firearms are gassy and are violent with brass.

The moral of the story is that you should adhere to what the manufacturer recommends you put through the firearm.

Reloadability

If you shoot a lot, you probably reload or buy reloads from a trusted ammo source. Reloads save you money over time but can be time-consuming for those who reload themselves.

Now, again, with malleability in mind, which shell casing is easier to reload? This includes being put through machines that crimp and press and all other parts of the reloading process.

If you guessed brass, then you’d be correct.

One of the ways that offset the cost of steel ammo vs. brass ammo is the ability for brass to be reloaded where steel cannot be reloaded.

Steel is a one-and-done type of deal. Brass will save your…you get the point. The cost can be further offset when you buy in bulk.

Mind you, some of these pros and cons are rifle dependent.

The long debate between brass and steel shell casings has been proven, and it’s clear that both of them have their purposes. I never run steel ammo in my firearms unless it’s an older AK, or I just don’t care for the firearm.

Again, if you’re wondering which you should run, refer to the manufacturer.

It’s worth paying attention and shooting accordingly in the long run.

What type of ammo do you run most often? Does it differ between handguns and rifles? Let us know in the comments!