Brass vs. Steel Cased Ammo – An Epic Torture Test

Lucky Gunner Labs ^ | 9/21/19 | Andrew

[ChildOfThe60s]

Brass vs. Steel Cased Ammo Test Summary

We acquired four identical Bushmaster AR-15 rifles. We chose the Bushmaster MOE Series AR-15 because it’s a widely available, affordable, and mass-market. Our team didn’t want something too cheap and of lower quality or something too expensive and of high quality since our goal is to help the most number of people.

We acquired 10,000 rounds each of the following ammunition (new production):

Federal 55gr – Brass-Cased – Copper Jacket
Wolf 55gr FMJ – Steel-Cased with Polymer Coating – Bi-Metal Jacket (steel and copper)
55gr FMJ – Steel-Cased with Polymer Coating – Bi-Metal Jacket (steel and copper)
Brown Bear 55gr FMJ – Steel-Cased with Lacquer
Coating – Bi-Metal Jacket (steel and copper)

We paired each ammunition type with a specific Bushmaster AR-15 and then fired all 10,000 rounds of it through that particular carbine (except for Tula; more on that below)

We systematically observed and tested various things, including (more details below):

At the start: accuracy, velocity, chamber and gas port pressures, chamber cast

After 2,000 rounds: accuracy, velocity
At the 4,000 round mark: accuracy, velocity
After 5,000 rounds: throat erosion, chamber cast
At the 6,000 round mark: accuracy, velocity
After 8,000 rounds: accuracy, velocity
After 10,000 rounds: accuracy, velocity, chamber and gas port pressures, throat erosion, extractor wear, chamber cast, barrel wear

We logged every malfunction of every rifle-ammo combination

The rifles were cleaned according to a preset schedule and temperatures were monitored and kept within acceptable limits (more below)

We sectioned the barrels and otherwise made unique observations after the test was complete

[ChildOfThe60s]

This is fascinating. The thoroughness, the methodology, the precision are all impressive.

If you've ever wondered or debated the usage of brass vs steel, you will want to read the whole thing.

[ChildOfThe60s]

It was annoying to have to reformat to get it readable.

I see that I missed TULA in the ammo list but it’s there in the article.

[null and void]

For the readers, TULA is between Wolf and Brown bear in the table posted:

Federal 55gr – Brass-Cased – Copper Jacket
Wolf 55gr FMJ – Steel-Cased with Polymer Coating – Bi-Metal Jacket (steel and copper)
TULA 55gr FMJ – Steel-Cased with Polymer Coating – Bi-Metal Jacket (steel and copper)
Brown Bear 55gr FMJ – Steel-Cased with Lacquer Coating – Bi-Metal Jacket (steel and copper)

Happens to all of us...

[bk1000]

All I know is my Bushmaster AR15 does NOT like Wolf coated steel ammo.

I don’t know why.

[mythenjoseph]

Great article , Thank you for Posting...good read.

[Smellin Salt]

Good article. I’ve always wondered what the difference is.

[Roman_War_Criminal]

I love studies like these.
Glad they used a chorno to measure velocity.

NATO/Israeli ammo almost always has the most consistent results with 5.56 ammo.

I shoot Ak’s so my guns eat everything up no matter what. Steel, Brass, lacquer etc.

[Spktyr]

Let me guess, feed/extraction issues?

[Eagles6]

Very good!

[Blueflag]

My Bushmaster AR-15 is my workhorse. It has proven to be a reliable workhorse as well. Glad to see them perform well in this test.

My Bushmaster AR-10 in 308 gave me fits with cases getting stuck in the ejection port, until an Army vet gunsmith/armorer fixed the problem in less than 5 minutes by polishing excess bluing out of the chamber.

Flawless since then.

They were great rifles that sadly didn’t float; lost in the lake.

[ChildOfThe60s]

shoot Ak’s so my guns eat everything up no matter what. Steel, Brass, lacquer etc.

There is something to be said for a little *less* precision. LOL
Suppose you had to gather all the people in your neighborhood, most of whom probably have none to minimal experience with firearms, and give each a battle rifle to defend the area in a disaster.

And then you had to leave it to them to keep the rifle operational, would you give them an AK or an AR?

[Joe 6-pack]

I’m not surprised at the outcome. My limited experience with steel case ammo + a lot of literature I’ve read leads to one almost intuitive conclusion. Brass, being softer, fire forms to the chamber and in doing so, helps clean any residue left in the chamber from the preceding round. Steel, being harder than brass, allows some fouling of the chamber with each round. Not as big a deal with a slightly tapered charge like a 7.62x39, but with a straight walled case like a 5.56, it becomes more problematic.

[datura]

Operationally the AK, for short range engagements especially. My AK loves Wolf ammo, but now my ARs will only feed brass.

[ChildOfThe60s]

Let me guess, feed/extraction issues?

After reading this I figure I will order an upgraded, high performance extractor spring. Cheap and easy to replace. I've certainly put more than 2,500 rounds through my Rock River Arms AR-15.

[PROCON]

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[PROCON]

Great informative article, thanks!

[dynachrome]

Lacquer coated ammo always jams my Mosins.

[Tijeras_Slim]

Lucky Gunner has some of the best gun content on the web.

[Lurker]

Thanks.

L

[Blood of Tyrants]

That was great! Thanks for finding and sharing this.