Its 0 today before figuring in the 20-35mph wind chill. I dont mind the cold but its a bit mutch to be sitting at a bench or laying outdoors and shooting. Luckily I have a machine shop with a open lane thats 100'. I am in a residential zon but I would feel safe shooting CB shorts indoor out of my Marlin 80 to keep my skills up. I would like to bend up a backstop to catch the bullets and put a sheet of 3/4" ply behind that. The back wall is 2 layers of steel siding with insulation sandwiched in between. Am I missing out on anything? Does this sound safe? I have never tested so I dont know what a CB short is capable of going through.