Also Cast bullets can be fired in Gas operated firearms with very little leading issues. I have fired them in an M1 Garand, M1 carbine, L1A1, DPMS LR .308, AK47s, and SKSs And a 1919 belt fed. These are all super sonic loadings that function the action of the gun. The only leading issues were the 1919 and 1 AK47.
I use a 130 Grain Lyman in my Model 1 upper, and it has run great on my M-16. I haven't put more that 200 rounds at a time through it, but it has all been on auto and cleanup isn't any worse that a suppressed 5.56 upper.