Hi drew.
I do enjoy seeing things people produce for them selves and cutting out the expensive manufacturer and the middle man. I hope you do not mind me pointing out one small detail that I think you should be aware of which is the upper arm Brass stop. Brass and Steel do not make good bed fellows and especially where the slightly acidic environment of gun bores are concerned especially if the bore is not Chrome plated. To put it in a nut shell standard steel barrels and microscopic brass particles that could possibly be left in the bore after using your gauge can sometimes lead to some electrolytic action taking place encouraging rust spotting, which can be more easily produced in mix metal barrels i.e. Damascus and twist. This is not a problem with bore cleaning brushes because they are made of the less reactive bronze. So I think that replacing the stop with one made out of Steel or Bronze would be a wise move.
Damascus
