Anyone with respectable machine skills could make a Sten in an outdated machine shop quite easily. The plans and dimensions are out there.
Anyone slightly better equipped can produce their own AKs. And do. There's video out there of tribespeople in Pakistan making their own guns, in a forge, with rough casting, trimming tools, and hammers.
They were even making copies of Norinco copies of Tokarev TT-33s. Probably questionable metallurgy, but it'd shoot, and the 7.62x25 round would go through a k-pot.
No, there's no "making them go away". People who wish to use force will always be able to make guns, draw casings, cast bullets, and load them. And use them.