Dave,
Sorry but I have to ask, inquiring minds want to know - In what way does shooting burning titanium shavings at 900 fps replicate impact cratering?

The cratering is caused by energy, a result of the comet's speed, no? (mass x velocity^2).

I think the highest velocity rifle one could find would be a better test for impact cratering. Easier to chrono too, so one could do the math to estimate impact energy.

Where's Rock Doc?

BTW, This crazy shell is supposed to burn all the way downrange, but instead is going to be fired point blank into mud? Yikes.