A backstop for decelerating and trapping projectiles includes a support structure having at least one bin shielded from incoming rounds. A trapping medium, such as a resilient granular ballistic medium and a hydrated SAP gel, is disposed contiguously on an upper surface and within the bins. Bins are defined by transverse baffles spanning the width of the backstop. The baffles are preferably constructed of a non-ricochet material. Vibrations will urgetrapped rounds downwards into the bins. In embodiments, the lower surface of one or more bins declines toward either or both sides of the backstop, such that vibration urges spent rounds towards collection points along the sides of the backstop. Access ports may be provided in the backstop sidewalls proximate these collection points to allow for removal of spent rounds. The volume removed may be filtered to reclaim projectile trapping medium for reuse.