A pole lathe re-enactment.
Powered by the foot-treadle + that long springy branch.
An Asterix and Obelix kind of situation!
Hand-carving a rifling guide- very impressive and resourceful.
The second picture shows the guide in use; the helical fluting is translated to a cutting tool inside the iron barrel. The lengths folks would go to eat birds for dinner!
source: contemporary makers