If a magnet sticks to the projectile then it is.
Lead is non ferrous.
I did not realize that there was such a thing as bi-metallic BULLETS?? I knew about the steel cases, but I wonder whether the Barnaul 168gr SP are bi-metallic?
M14/M305 is designed to shoot military spec ammo. I remember most of them are copper washed steel case, berdan primer, 150g FMJ.
I shoot 500+ rounds mil surplus ammo last month, no issues at all, only 7-8 cracked cases. Since you don't reload them, no need to worry