I'm using this old steel drum but don't need that depth, so...I made that plug on the sawhorse to to take up space in the bottom of the drum.
Here I cut away the center of the steel lid and left enough room around the edge to screw on this plywood front.
All that black stuff on the tarp in the next picture under this one is the rubber garden mulch that I put into the drum. Eventually the center of the plywood will shoot out so I layered the plastic bags the mulch came in on the top of all the mulch...the plastic will keep the mulch in the drum when a hole develops in the center of the plywood.
Here the lid is on, mulch and plastic bags will go inside under this...this is the rubber floor tiles I get from the Home Depot, I cut them to fit the lid and staple the rubber mat to the plywood...this makes a great target backing for paper targets, just use 1/4" staples for the paper targets...when it eventually shoots out in the center, I start mounting the targets on a small piece of cardboard and that provides backing for wadcutters and SWC's to cut clean holes. Even the RNFP's will punch clean holes the size of the FP.
Here it is mounted on this old wagon. This helps when I need to mow in that area...this is a heavy target.
More than practice, I constantly use this behind my shop...place the Chrono in front, get the speed readouts and see if your load will group all at the same time.
Very handy....when I took the old target down I got back 18 lbs. of good boolit metal...not range scrap, good tin rich metal.