Do they make bullets for a enders royal service 12 G double barrel?

That should be a shotgun, and it will shoot 12 gauge shotshells or slugs, available at any sporting goods store and most department stores. You should check with a gunsmith to determine chamber size. It may also be marked on the barrels, or underneath them, as to chamber length. Some older 12 gauge take shells that are 2-9/16" long. Most modern ones are 2-3/4", and some will take 3". Each length chamber will take any shorter length shell as well.