Normally the flat surfaces of the chopper lump barrels that make up the breech end of the barrel set are normally brazed together! This sometimes done by wiring the two together after painting the mating surfaces with a mixture of flux, and powdered brass, then placed in a fired or electric furnace and heated till the powdered brass fuses the two together.

With the shoe-lump, barrels this section is made up of four parts, for the breech end of the quarter rib, the two barrels, and the shoe which is a saddled platform with the lumps on it’s bottom. or dovetail sometime three parts and sometimes four parts, Both these are painted with the mixture, wired together, and done in the furnace as well. The rest of the barrel set is usually soft soldered together wedges, and ribs front sight ramp.

Below is an example of Heym shoe-lump barrels.