While I can not give you a specific brand or model number (don't own an X-Frame) I would make sure which ever one you decide on has adequate weight dispersion qualities and maybe even padding on the shoulder strap as those guns are real heavy. I would think that the wider the shoulder strap the better it would be at doing this. I can only assume you are using this as a hunting rig and will wear it exposed and in full view so concealment should not be an issue - hence the size and width should not be an issue either.