Friday, January 11, 2013

Brass vs. Steel in your AR-15

The folks over at LuckyGunner posted results of a test between brass-cased and steel-cased ammo in an AR.  I'd say it was fairly scientific and enlightening, to say the least.  They burned up something like 40,000 rounds, so I'll take that to mean they were serious about getting a decent answer.

Long story short - brass appears to be more reliable, but steel can get you by in a pinch.  I was especially surprised by the lack of extractor wear between steel and brass cases. 


  1. Russians shot way more than 40,000 rounds in AK-74s: more like billions of them. Although steel-cased 7.62 was introduced in 1960s, we still shot out remnants of brass stocks as late as 1987. Nonetheless, brass-cased 5.45 never existed and they went through Afghanistan with it, not to mention Abkhazia, Chechnya, Georgia etc.

    The trick is that the "steel-cased" ammo is more like "iron-cased": the material of it is very soft. And it has to be, because of the case expansion. In case of 7.62x54R the expansion is enormous, and yet the case has to work without cracking. When such metal meets the hardened steel of the extractor, it has no chance.

  2. The extractors appeared unworn, regardless of case type. It's also difficult to compare an AR-platform to an AK-platform when talking about steel vs. brass ammunition. I would assume (I read The Gun, but it's silent on the topic) that the Soviets took things like steel cases into design consideration when the AK was 'born' (perhaps even when the SKS was being developed, and maybe even earlier firearms). It could also be that steel requires different loading parameters that are not fully compatible with AR gas systems (DI or piston). I really don't know.