I live on a farm and I rarely go to a range and shoot; I just walk about my back door. Paper and cans are a pain since you either have to go clean them up or(hides from environmentalists) keep shooting them until they sink. I found one of these 5lb flat plate weight laying around the garage that used to go on a 1inch weightlifting bar. We rigged that up where it cant fall over and had some fun trying to shoot through that little 1 inch hold in the center of it with a .22. It's got a nice high-pitched "dink" when you miss the hole and hit the weight. A single weight like that would be cheap at walmart 6-10$. I guess if you just wanted "reactive" for the sake of it you could pack that center hole full of flour and shoot it out. You should be able to find 5lbs of flour for less than 2bux.