Nothing is really keeping them out; they would be legal to ship here as they are just screws. It's just that 90%+ of all their stuff would not be legal to ship here so they don't set up there systems to ship anything here. When I go to fill out my shipping address their is a drop down menu where you need to select a US state. It's understandable from their viewpoint I guess; not like they would make much money on selling $2-5 generic, non-firearm related parts so they just don't factor it into their ordering system.

I'm really surprised Boyds would not stock and sell them like everything else, they state to just go pick them up from a local hardware store but I don't think they realize how rare these are. I went to a couple of hardware stores here this morning and they don't even have these screws in a catalog they can order from. They got bigger ones and smaller ones, but not these unicorns.