A good friend that just passed away owned 10 4 bores, 7 single shot and 3 doubles. The T. Mullin had 48" barrels and a Holland & Holland had 42 1/8" barrels. I measured all of the bores and chokes and most were around .938 and one was smaller at .910. I don't know what the doubles weighed but were very, very heavy.
He wanted me to shoot one sometime. He was reloading them and had a fellow in New York state make shells for him, paper case and a copper head. He gave me one of the hulls, makes for a great conversation. The rim diameter is 1.180 and the base diameter is 1.065. This compared to a 10 ga., rim dia. .910, base dia. .850.
He will be greatly missed.
