The trap consists of a simple steel box about 20"x30" with a 10 ga. bottom and 4" 12 ga. sides. Then a 3/8 piece of plywood top fastened on with nuts. Standing the box on edge, I fired four rounds from my .22 rifle into the center of the plywood. then I removed the plywood to check the contents. Lying on the bottom was little tiny pieces of lead and wood splinters. The largest piece of lead was the base of the bullets (4) about 5/16 diameter and the thickness of a heavy piece of paper. Everything was trapped inside the box. Yesterday, I fired 20 rounds from my .22 pistol into the trrial trap. Same results. Shooting straight on into a steel plate make .22 bullets explode into tiny fragments. Shooting at an angle would probably be a different matter. But that's not how I'll be using it.
I'm now about to make a permanant trap slightly larger 24"x48" with 1/4" plate bottom and 3/16" x 4" sides. I'll mount it on end so it will stand 24" wide and 48" high on a stand with casters to make it moveable.
Photo of the trial trap.

