Steel bullet traps have been used for over 90 years in commercial and law enforcement/military ranges, however, rubber, particularly granulated rubber, has seen tremendous growth over the last twenty years and has become the most preferred for commercial and law enforcement traps.  Advantages to rubber bullet traps are that they tend to be much quieter as the rubber acts as a sound absorber and much cleaner as the rubber encapsulates shot rounds in whole. Moreover, the cleaner air generated by the rubber type bullet traps is much less taxing on ventilation systems resulting in longer life spans for ventilation filters.  Rubber type bullet traps are preferred for up and close training as the angle of shots entering the rubber does not create any type of ricochet hazard. Last, rubber type bullet traps tend to cost a fraction of the price per linear feet of steel traps and, in most cases, take up a fraction of the space required of steel bullet traps.