Barrel boring is an interesting topic in itself. Very early on, it was a closely held art form. In 1775 John Golcher was hired by the Council of Safety of Philadelphia to teach boring at their newly established gun factory. Wallace Gusler, a modern smith, claims they would easily use 13 drill bits for a single barrel. These were constantly breaking and had to be resharpened in the shop.
As it became a more specialized task, apprentices were often first put to work boring barrels under the supervision of older journeymen who were considered too old for other tasks.
It is amazing that more barrels and chambers do not exhibit "peculiar" dimensions.
Pete
