Bullet traps made of steel sheets have diverse construction. The most common designs are lamella and the snail also called cone bullet traps.
Lamella bullet trap

Lamella bullet traps are made of steel plates, inclined at an angle in the direction of the line of fire with a properly chosen thickness of the sheets. Bullet trap can be covered with anti ricochet screens made of straps, rubber or gel panels.
Cone bullet trap

Cone bullet traps have a relatively small tilt angles of metal sheets. After bullet hits the top or bottom plate it moves across the surface of the sheet in the direction of the inlet slits to the trap tray.