Aluminum could maybe be made to handle .22lr type pressures, but certainly not .223rem or bigger. ? The Alexander Arms .50 Beowolf lower is made out of alu

Aluminum could maybe be made to handle .22lr type pressures, but certainly not .223rem or bigger. ? The Alexander Arms .50 Beowolf lower is made out of aluminum. http://www.gunblast.com/50Beowulf.htm http://www.gunblast.com/50Beowulf.htm You can also buy single-shot .50 BMG uppers that bolt right onto regular aluminum AR-15 lowers, though of course you can't feed .50 BMG through a 5.56 magazine well.