It's a 7.62x39 with 30 degree shoulder, fire formed. The body of the shell is the same as 6 MM PPC or 22 PPC-just necked out to 308. Since 7.62 brass is so plentiful and popular why not. Best combo is 1-12 twist with 125 gr-130 gr bullets. I have shot bullets from 110 gr - 190 gr. If someone is interested I will give more detail.