Very new at this, but a five-gallon bucket with a bunch of too-ugly-to-wear ties as a backstop should work just fine. MIne is a 50 plastic drum with an old bedsheet hung in it. The hole in the side is about the size of a five-gallon bucket. The round profile means if I miss that hole, at least the ricochet is short and not straight back at me. (yeah, it happens. I am new to shooting steel balls) Hehe!