The Wilson Combat Reverse Recoil Spring Plug is designed for a 1911 Government model with a bull barrel. This supported reverse recoil plug will fully support a 5" bull or tapered cone barrel when in battery. The open end plug is perfect for any full length guide rods. The collar style rear profile will require gunsmith machining to fit most factory slides.FeaturesOpen end is perfect for full length guide roadsPrecision machined from solid stainless bar stockSupports 5" tapered cone barrels (when in battery)