GG,
Did you also machine a half scale Mt. Howitzer barrel from bronze, or am I just remembering that you machined the cast barrel to finish it?
All of the bronze ones I have done were castings which were machined all over inside and out; no unmachined surface on the finished barrels. I have also done or supervised the construction of steel half scale mountain howitzers which were machined from solid stock and had the trunnions welded on.