In regards to firearms, it doesnt really matter. Spray welding is an atiquated method when you have micro precision laser welding and TIG. Plus, the results are ugly as shit. The material used turns the bite on the hook a funny yellowish color, fugly. Ive had two guns with intergral hinge pins micro precision laser welded and fitted up, swear to God you cannot tell any work was done. And both hooks are at almost 100% contact. Thats precision.