Grizz,
I'm gonna really sound like momma hen here, but it's not even smart to shoot that soft of steel with your gun at 100 yards. You don't know where that bullet is going to go, especially with the weight of that 1" steel.
If you can afford that camera setup, you can afford a piece of at least ar400 plate, hung so it's angled downward. The reason I said 400 is because the speed and diameter of the bullet shouldn't pock it like what you have, but get 500 if possible.
I think on the Hide website, not the forum part, LL has a video of a guy shoooting a 50 cal at short distance, watch it.