Why are bullets made up of brass, not aluminum?

There are many benefits to using brass bullets instead of aluminum ones when shooting firearms — including improved accuracy and performance

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VMS Racing 50 Cal Caliber Brass Finish Bullet Antenna Heavy Gauge CNC Machined Billet Aluminum Short Compatible with Harley Davidson Road King Electra Street Glide Touring Models with Tour PAK (ONLY)

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brass case, aluminum case, steel case, doesn't matter, Glock will shoot it all : r/Glocks

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Why are bullets made up of brass, not aluminum?

Why isn't aluminum used for ammunition casings, since it is less expensive than brass and lighter? - Quora

Why aren't ammo casings made out of aluminium instead of brass (brass which is way heavier than Al)? - Quora

The Truth About Brass vs. Steel Ammo - Pew Pew Tactical

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