I tested today to see what penetration to expect from the hredded rubber used as a back stop for my garage range. Using a cat litter plastic bucket 14 inches deep, I placed paper markers at the 4 and 8 inch depths as I filled the bucket with shredded rubber chips ... not nuggets, shreds. Atop the rubber I placed a Cheaper Than Dirt (gougers that the are now) catalog then the plastic bag emptied of rubber bits.
At ten feet I fired a CCI Stinger, then a 22 Winchester dynapoint magnum, then a 73 grain 32 acp, then a 124 ball 9mm into the rubber filled bucket. The .22 rounds made it past the 4 inch paper but disintegrated before reaching 8 inches. The 32 acp Fiocchi made it just past the 8 inch paper and was found in tact, while the 9mm ball made it to 12 inches and had a slight deformation where it hit perhaps one of the .22 rounds or the 32 acp jacketed round.
I'm going to build my backstop 4' x 5' x 18 inches deep, on a casters frame so it can be rolled out of the way when not in use. The frame will raise the stopper18 inches off the garage floor and there will be a panel in the end that will allow higher caliber rounds to be test fired into the long-way shredded rubber. The face of the stop will not be shot unless there's a flier when shooting at the 12" x 12" x 12" steel bullet trap in front of the stop.
Thought folks might like to know what kind of performance to expect from the shredded rubber bullet trapping system.
Interesting.
Just stay safe out there.
What is the material on the face of the stop?