Any tricks to make steels more reactive?

[EXPRESS]

I'm setting up some steel targets from 2800 yards out to 3521 (2 miles) and would like to find a way to make them "more reactive" these will be big sheets of 4mm mild steel. I'll paint them white, using a brush, not a can, which I find give a much better coating, and that paint chips off better too.

So has anyone ever come up with a way to get a better impact signature on steel? Any kind of powder you can get to stick to it, or paint methods that will make bigger flakes chip off?

 

[WildRose]

Lyme white wash is a powdered lime product you wet and then apply like paint which "poofs" pretty well when struck.

Gypsum based dry wall mud wold work well too.

 

[rafterfp]

Drywall mud has worked for me but I've only used it out to 1800.

 

[wwbrown]

Maybe tape a bag of tannerite to it, that ust get it more reactive when the tannerite is hotit, please provide videos.