I have heard using the BRASS casing is the best thing for an AR-15? Should i just use Brass or Steel?
No. People who say that don't use steel cased ammo. It it said its harder on the extractor. I don't see how. Its dirtier because it doesn't expand like brass does but the steel casing is still softer than the steel of the gun. That is a mild steel which isn't as hard as what most people are thinking of.
Many people have to jam a cleaning rod muzzle end first, using a hammer to bang out steel cased ammo out of an Ar rifle. This has happened to me 3 times and will Never happen again. It said its harder on the extractor, well that is not so but the case will be badly damaged by the extractor and I don't think that is a good thing for any extractor. Any individual pushing steel cased ammo must be selling it...Don't Buy It!!!
Unfortunately, steel case ammo being actually harmful for your AR is a quite popular myth. Steel is less malleable than brass. When you fire a brass cartridge, the brass expands to the chamber walls and helps block any expanding cases from dirtying up your chamber. When firing steel cartridges, the steel doesn't expand as well as brass, so you probably will end up getting a little carbon residue in the chamber. This tiny amount of carbon in the chamber is enough to make extraction of brass cased ammo more difficult. When the brass expands to the dirty chamber after firing steel ammo, it conforms to the carbon residue somewhat, increasing friction. This small amount of friction is sometimes enough to make a normally okay AR malfunction when attempting to eject a fired cartridge. So to give you a short answer, use both! Just make sure to really clean out the chamber after firing steel ammo.
Two reasonable answers here. But let me say this...I just don't like the idea of steel touching steel at a high rate of speed (like when it's being cycled in and out of the chamber of a rifle). I can't help but feel that some sort of erosion is going to occur to the chamber of the rifle - which obviously isn't a good thing. If it were me, I would stick with firing brass casings only. The only gun I would fire steel casings through would be a cheaper SKS
