New here so just sharing my completed Slr build
Metal gears, tight bore barrel + longer outer, M90 spring, 11v battery, AKA hop up hidden inside silencer, 4x flip up scope + red dot sight and a torch/laser combo with pressure pad.
My current project is converting a M97 shotgun into a trench ■■■ with real wood stock and pump. Possibly a metal heat shield too. Will post results when its done.