for moving target's down range get some used or new if you want garage door opener motor's. also if you have access check out some concrete sewer piping. then you set your shooting position down a few feet lower than tube so you can do either sitting or standing position's. you can also use a hi-flow exhaust fan( look at uesd resturant equip. suppliers) for down range venting.
by the way the epa and haz-mat people consider anything less than 55gal drum as dumpable at your local dump/recycle( oil etc) if you seal it in 5 gal or less container's you should have no problem getting rid of it. at this time osha and the epa ONLY have reg's for lead paint! i know as i have been looking at doing an indi\oor range for the gen public.