Wayne, most folk do not realize adhesives are considered a mechanical fastening system. Just trivia.

Best adhesion always attained by scuff sanding mating surfaces, removal of any coating prone to peeling off under shear or tension loads, thorough clean with a non-residue degreaser such as brake cleaner, air dry, and apply adhesive, clamp and allow full strength cure (especially on a sawed off shotgun!) which may be as long as 7 days.