Originally Posted By: wyobirds
I remember reading that O/U's were invented and produced prior to SxS's.
Do any of you historians know?


Very tricky to make an over/under muzzleloader and few gunmakers produced them. The side by side layout lends itself readily accepting the twin locks.

I can find no patent for an over/under or a swivel breech that predates even a Manton side by side flintlock.