Will a non 1917 barrel mount in a 1917 frame?
Say a Mod.25 type.
I know I have seen a post answering this,but so far
I have not found it.
If the answer is yes,any suggestions where to find one other than GB?
Yes and no. Threads are the same. The problem with a Model 25 barrel would be the target rib. It would stick up above the 1917 frame and look fugly. (I made one work with a cut off and reshaped 1950 target barrel once!).
New production (reproduction) 1917 barrels should work and be available from the factory. I personally don't like the profile of the new front sights, though. You can see pictures on the company website.