UK straight pull Bren?

[Vincent]

You could make a new body using another method. Two side plates, top plate, barrel support, etc. Then weld them together. No gas system, no barrel nut, just press and pin the barrel in. Mount the bipod on the barrel or on the barrel support and have it fold forward under the barrel where the gas system was. No return spring or buffer, just firing pin/striker drive spring. Striker stays on the sear when the bolt is open. Mechanically there’s not much to it. CNC would make quick work of the parts, but you could make them on a manual mill.