This is the problem with metal backing plates. Craters present a ricochet hazard...so the best answer is to either use something that will not crater (within a reasonable lifetime) or something replaceable (like dirt).jimlongley wrote: The resulting dent spit lead back uprange, so it was eventually consigned to the barn, where it was still rusting away 30 years later.
AR plate is popular, but expensive. Anything from sand to crumb rubber (shredded tires) will work if you get enough.