Shroud ID and thread information for Umarex Origin wanted for suppressor build

I started with the design shown below. It took about a half-hour, the threads took the longest. Then I had a totally different idea for the suppressor. However, for that I need to know the ID of the barrel shroud and the thread information for the endcap.

Does anyone know those?

Here was v.1, but I think I will go in an entirely different direction.

Cutway Suppressor.1644423607.jpg


Yes, I have an unused suppressor tax stamp that I never got around to building. I have also never printed the completed suppressor, just the cut-away model.