From John Robb comes the startling news that guns can now be made with 3D printers. "Havenblue" has printed several assault weapons and they fired fine. This rather clearly changes everything for insurgents, revolutionary groups, etc. Maybe it'll be like designer drugs, where the chemists stay ahead of the law by making drugs that aren't illegal yet. Designer assault weapons could probably be manufactured so they are legal, at least in some states. As for changing a semi-auto rifle to a full auto, maybe that'll be easy now. Just print the part you want. Or perhaps we'll see entirely new weapons, designed for specific one-time purposes, being made with 3d printers, used, thee disposed of.
It's now possible to print functional weapons at home. This is going to progress rapidly now. Think: global file sharing of designs for servicable weapons, from pistols on up to ?, that can be printed at home. What you can print -- from the materials to the size/quality of the object to the completeness (snap together construction) -- is already moving forward quickly. The weapons effort will just be along for the ride.
A commenter says this means you can now literally beam devices from one physical location to another.