I shoot my own cast 55 to 65 gr boolitz in 4 different Armalite rifles in 5.56, I have 3 different 4 and 6 cavity molds I generally feed them with surplus WC844 and CCI 41 primers. I have also used Re7, Re15, 4198, 3031, 4895 and 4320, with 4320 I have succesfuly shot cast at 2850 from a 16" 1x9 5.56 DPMS barrel.

Cast will work fine in your 1x8 barrel regardless of what chamber you have. If you have a 1x8 twist barrel chance are very good it is not a 223 but a 5.56 chamber.