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+--- Thread: Why aren't ammo casings made out of aluminium instead of brass (/Thread-Why-aren-t-ammo-casings-made-out-of-aluminium-instead-of-brass)
Why aren't ammo casings made out of aluminium instead of brass - ZellaHyday - 01-13-2022
Casings have been and still are made of aluminum. The ones that spring to mind are the popular Blazer line by the manufacturer CCI.
The main reason brass is used is the elasticity of the metal allows it to expand and press against the walls of the weapon’s chamber when the bullet is still in the barrel. This seals the breech ensuring hot gas doesn't leak out of the chamber. When the bullet leaves the barrel and pressure drops brass shrinks away from the chamber wall slightly allowing easy ejection of the spent case.
Both aluminum and mild steel will do the same thing. However those spent cases can't be easily reloaded. Brass cases can be.
There's also a sight element of tradition. The first metallic cases were made of brass, albeit with a much higher copper content. Many shooters will only use brass casings. They feel other metals cause excessive wear on the weapon. I personally have never found this to be an issue.
In my experience weapons with fluted chambers actually work better with steel case ammo.
RE: Why aren't ammo casings made out of aluminium instead of brass - aluhm - 01-13-2022
They are. But you’ve structured your question in such a way as to assume aluminum is superior, and they don’t sell well because the opposite is the case (sorry, it was too easy!). Ductility is the main advantage for most. And of course those of us who reload won’t consider anything but brass.
RE: Why aren't ammo casings made out of aluminium instead of brass - toyota1515 - 01-13-2022
The malleability of brass has been mentioned, but there is another feature brass has which is important and has not been mentioned. This feature is low friction. Aluminum tends to stick when rubbed on another metal while brass moves smoothly. This allows casings to be easily ejected and helps gun actions move smoothly.