We ourselves produce our guns barrels of high-quality stainless steel grade 4140 as follows:
1) Barrel blank heat treatment (normalizing).
2) Barrel blank deep drilling.
3) Bore sweeping.
4) Bore Honing.
5) Buttoning (formation of grooves by forcing down the mandrel).
6) Barrel honing (fine-tuning).
7) Chamber sweeping.
8) Barrel tempering ( internal stress relieve) in the oven protective atmosphere.
9) Barrel Carbonitriding.
10) Finished barrel hot chemical oxidising.
Flutes can be cut on the barrel at the customers request.