Set up enough plywood sheets to create a shooting barricade as long as you'd like. To this kind of wood you can nail targets, silhouettes, solid shapes and other objects.
Position your wooden barricade in front of a hill, compost mound or other soft earthen backstop, called a "berm." Without this, your bullets will penetrate the wood and keep flying.
Use cinder blocks, at least two per wooden sheet and spaced to the ends of the wood, to keep the plywood upright and sturdy.
Replace the wooden panels whenever they get so damaged that their structural integrity is almost exhausted.