Good fun trying to sus it though. Bit like an "identify this object" quiz for gun nuts.
The barrel looks like a modern "green mountain" lump. Unscrewing the breech plug and measuring and inspecting the thread would show if it were modern. Old threads were not a crisp cut unlike modern tungsten tooling cut, and they tended to be coarser.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane