Necessity is the mother of invention, and we need to invent something else because of these mothers.
The AR-10 in the picture has the original upper and lower. Which is missing the point.
Ok, so I admit be being uninformed about the new rules up north. If this sort of thing were to come about in the US, folks would get an unfinished AR15/AR10 lower and a corresponding stripped upper and modify them slightly to work in a non semi-auto fashion. (see prior post with bastardized AR10) The gun would not really be a AR15/AR10 and would certainly have no markings to that effect.
Down here the goal is to be several steps ahead of folks like Diane Feinstein.
When the barrel extension is unscrewed from the barrel, the barrel shank threads are rather small in diameter, compared with most bolt action receiver threads. It would be necessary to make an adapter sleeve/collar/adapter to screw onto the barrel, which would fit the new receiver. Many AR barrels are chrome lined. This could affect any chamber reaming required to set headspace.
It would be necessary to make an adapter sleeve/collar/adapter to screw onto the barrel, which would fit the new receiver.