That can be a real headache couple of years ago, but with the blooming of domestic 3D printing technology, I can easily imagine someone can make a decent build out of printed parts and a pvc pipe, if one has the will to do it (indeed it is a time consuming task).
Plus, the files are readily available here on the forum 3D-printing section, no reason not to give a look into it.
Countries that banned replica firearms/ mock-up props outright are out of the question sadly.