We have long gone past sensible gun restrictions. Background checks at gun shows and for business sales are sensible. I don't even have a problem with the tax stamp system for short barreled rifles/shotguns, machine guns, and Any Other Weapons. But the ban on adding new machine guns to the transferable pool is asinine. Arbitrary bans on how many rounds a magazine can hold are just plain ineffective, here in Colorado it is being proven once again how such a ban does nothing.
As far as your hysteria of non-metal-detectable guns, that is a fairy tale just like the fear of blood in the streets over the last 20ish years as concealed carry laws became the norm. Barrels for a good long time are going to be metal. All these defenders of the 2nd Amendment are doing is printing receivers, which don't have to handle high pressures. In addition it has long been legal to make your own firearms, I can legally buy an 80% finished receiver and finish it myself. In this case I don't have to put a serial number on it, as long as I don't have a business I can even sell the occasional one. For an AK you just need a jig to bend and drill the sheet metal and some rivets, for an AR-15 it requires machining which can be done with typical home equipment.