It's a circa 1807 flintlock musket that's got the cartridge upgrade... And it's still being used all over the place today...
And in upcoming action-shooter video games taking place in desolate, mutant monster and radiation infested post-apocalyptic landscapes set in Eastern Europe, like any future Half Life releases, Tarkov, etc, it will continue being a mainstay long range weapon because of it's common availability in real life...
Last month a Russian soldier carrying one was spotted swinging it at an incoming FPV drone like a baseball bat. He missed the drone but the operator wanted a denser target around 20 yards from him and airbursted the vehicle in a group of soldiers...