I've just registered and this is my first post. Probably should lurk for several weeks before saying anything, but this subject is very familiar.
Straight rifling goes back to at least the middle of the 1700's, and was not unusual in pieces made in the American Colonies. It seems to have been a German concept especially with some of the Moravian and German gunmakers in Pennsylvania and North Carolina Colonies. I have a contemporary 1770's .60cal flintlock with straight rifling. This piece was duplicated from an original RevWar Militia piece that is on display at the American Museum in Valley Forge. Original purpose for straight rifling aparently was to provide a collection groove for black powder residue allowing multiple shots to be fired before swabbing out the fouling.
