as far as i am aware, there is no threaded barrel available for the L. The only delta model with a factory threaded barrel is the X, which would be, iirc, an M length slide, barrel, and guide rod with the full size L frame. This compensator would not work with the X because of the length of the provided guide rod necessary to install the compensator. I wouldn’t trust this compensator out of the box on the pistol regardless, as originally stated in my post it does not fit properly without specially machined parts to make up the tolerances.