Reminds me of some thompson and sterling clones I once took a look over manufactured by the IRA out of sheet metal. If you literally just stick 'Glock' in to MidwayUK you just can buy every single internal part; couldn't see slides, frames or barrels (which obviously just leaves you with a pile of small bits) but the rest is there.
Also quite reminiscent of the AK an American built using nothing but after-market parts and the blade of a rusty old shovel to form and cut in to a receiver.