My last trip to my secondary range and I see this crater in the cement floor. Glad I was not there when it happened, especially sitting close. This range is actually part of a park and has collectively the most unsafe range "members" of any place I have ever been a part of. They are closed till spring but I might try to find another range . The part about not placing the finger on the trigger until pointed down range and are ready to shoot did not click with this individual.