Placing a Value on Non-Live Fire Training

In preparing for defensive encounters, live fire is obviously the best and most realistic training we can do. But live fire training is not always possible. What are the alternatives and their value? Rob Pincus examines the options -- .22-caliber conversion kit, .22-caliber pistol (not a conversion kit), Airsoft gun, laser gun, non-firing plastic replica gun -- and ranks their relative value as trainers.