A modified AK-style rifle including a receiver body with a back end having a first threaded cylindrical cavity and a second cylindrical cavity located below the first threaded cylindrical cavity. A lower portion below the first threaded cylindrical cavity has a width that is narrower than the upper receiver section to allow for passage of a pair of parallel and opposing telescoping bars on each side. A trunnion is connected to the receiver front end and an ambidextrous bolt stop is attached to the receiver body. A removable stock is coupled to the first threaded cylindrical cavity. A first bolt carrier rail is attached to a first side wall of the receiver body and a second bolt carrier rail is attached to a second side wall of the receiver body. A bolt carrier slidingly bears on the first bolt carrier rail and the second bolt carrier rail. A gas block includes a short stroke gas piston aligned with the bolt carrier section.