A supply of "spent" pellets from today, will help.
Some of the lads use blocks of "duct seal" as the backstop/collector for their indoor shooting, whereas I have an 18" x 19" open front on mine, having a 3/16" x 24" square of steel set at an angle in a 1/2" plywood box box with 2"square slats holding the steel sheet. I staple cardboard over the open front of it for target support.
I've used it for initial sighting for all of my air rifles, ncluding the .45, but excluding the new .50 cal. I dont want and denying of the steel. It may not, but dont want to test my luck too far.
This "box" makes for an easy lead collection station, however the collected lead had quite a bit of paper mixed in it.
This easily burns off before making 1 lb. ingots.