GG, I was under the understanding that the forum would be moved, not split. There would be only one forum, not two, to split people up.
It is my understanding that there will be four forums (fora) in place of the one we have now. One essentially the same as this one; the others with specific themes which would get separate material from the general forum.
The Home Machinist board where I moderate the Gunsmithing forum created a separate forum for 3in1 machines, which had been posting questions on the General forum. 3in1 users tend to be newbies who have no machining experience and this split ended up having them asking each other questions that would have been better served by being on the General forum where the really experienced people were. Most experienced people hold 3in1 machines in very low regard and didn't read the 3in1 posts, thereby depriving the 3in1 people of their expertise.
I am not opposed to dividing the Mortar and Cannon forum into separate fora, but I think we would see the same segregation of experience because some material will be posted where other people will not see it.