I need to build a backstop inside a steel barn, with a dirt floor. Backstop will hold several hundred rounds of handgun ammo a week. Thinking about three layers of bridge planks, staggered, so the seams do not line up, sandwiched with fence T Posts. May also think about solid railroad ties. Thought about sandwiching sand or dirt between plywood. Your input is very welcome. I have one week to build something. Would rather build it once, and have it done with, rather than fussing with the project again in a couple months. This video shows something that seems to work well. [ame]http://youtu.be/5gCeOtK7X-w[/ame] Wanna kill these ads? We can help!