Often wondered how gold barrel bands are put on the end of a barrel.

there are grooves cut in the end of the barrel. The sides of the grooves are then undercut  so the grooves are somewhat dovetailed in cross section. small burrs are then raised in the bottom of the grooves. gold wire of the appropriate size is then pounded down into the grooves. this forces the gold over the burs and out into the dovetails, locking the gold into place. it is then sanded smooth and usually flush with the surface of the barrel.