Hugh,
I am a firm believer in what JAG is advocating. I, too, have built different AR15 platforms. The first was an FFL registered stripped lower receiver and a full kit (shipped through UPS with NO FFL paperwork) from Model 1 Sales. Everything went together smoothly. Anyone with any mechanical aptitude can do this. I next bought an EP80 and drilled and milled the lower with a drill press and Dremel tool. This, too, is easy if one works carefully. I have since bought two 80% aluminum forged lowers and a jig. I don’t mind the extra expense of the jig, as it will provide piece of mind while I drill and mill the lower. The bottom line is an individual can make an unregistered rifle that is LEGAL to own. They can be cheap enough to cache and reliable enough to depend on. The AR15 platform is made from a design that is easy to assemble and disassemble, clean, and shoot for the smallest frame adult. I feel that every home could benefit by having one of these around. The one thing that I would add is a .22 caliber upper or adapter for plinking. The ammunition costs less and shooting at tin cans or targets (safely) is fun, relaxing, and a good way to teach firearm safety and handling. – CDH