Loyalist Dave said:
As far as cutting a barrel, since we are talking trade guns, it would be quite easy, and would not warp the tube, to hot file it.
LD
Since you are a Sergeant Major, there are two rules one has to remember about Sergeants Major, that may be germane to the discussion.
1. The Sergeant Major is NEVER wrong.
2. When it is shown the Sergeant Major was misled or mistaken , REFER BACK to Rule Number One.
Iron Temperatures involved:
1. Iron begins to form scale at 760 degrees F, a low red heat.
2. Scale falls off Iron freely at 1750 degrees F a low end orange heat.
3. Hot filing is done at Orange to Yellow Heat, normally at least over 2000 degrees F, but higher than the temperature when scale falls off freely.
What this means is that hot filing the end of the barrel is going to form scale that falls off. That will require aggressive polishing at least, if not reaming, to smooth the metal in the bore near the muzzle after hot filing is done. I know Trade Guns were relatively cheap, but I doubt any owner would have accepted the rough bore after hot filing without getting it smooth again.
Further, the temperatures involved in hot filing are well above the plastic point for Iron and that means it would be easy to warp relatively thin gun barrels while hot filing them. Hot filing was/is generally done on thicker pieces of Iron.
Then of course comes the question was hot filing even DONE in the 18th century? In fact, it probably was not done until the 19th century after improvements in steel caused the price of hand files to come down a great deal.
Peter Ross, the longtime blacksmith at Colonial Williamsburg before he retired, has often stated that Colonial Blacksmiths probably did NO hot filing. With the access he had to research documentation and his practical knowledge of period blacksmithing, I will go with what he says.
Gus