Several print head assemblies allow for the inclusion of a BMG extruder, but do not account for the bowden fitting, and the bowden tube ends up mostly free-floating inside, with a very small part of the tube being aligned with the extruder.

This is a replacement fitting/insert that allows the extruder to be flush with the surface of your assembly but also holds the bowden tube in place properly.

I have included both a tapered design which adds a tapered spacer between the bowden tube and the extruder which allows the filament to be guided into the bowden tube, as well as without, so the bowden tube itself sits flush against the extruder.