Guys,
This is really a great discussion! Keep it up.
Dave,
I think that the longer barrel lengths (smoothbore) also influenced the small shot pattern. A short barrel, like 30", would give an open pattern; a moderate barrel, like 45", would give a tighter pattern; and a very long barrel, like 60", would give a very tight pattern. Today with those shotguns we load from the wrong end of the barrel - we use cylinder - modified - full. I think that this is the reason for those really long barrels on waterfowl guns, like the punt guns and market guns. Although, it would be interesting to determine how the 18th c guys were able to measure the differences in velocity.
Ron,
You have hit the proverbial nail on the head! When I clean/load the 56" barrel gun the gun sits at about 45 degrees as I am only 5' 9" and the gun is 6' 0". No resting the butt plate on your toes when you do this. Eventually the butt plate heel will wear, but probably not in my lifetime! At my local shooting range the ground at the firing line is gravel, so I lay an old sheet of cardboard box to rest the butt plate on.
All the best,
Jim