I've never used it on shotguns, but have on other engineering and "cosmetic" applications. It's big advantage is the ability to take the metal deposition process to the job, rather than t'other way about, so big heavy things like generator / armature bearings can be repaired without transporting them to a plating shop.
The process has been developed over the years by the
DALIC company.
I can't really see it as being worthwhile for obliterating pitting; you'd have to deposit / hone / deposit / hone several times to get a decent result. When I've filled corrosion pits on hydraulic shaftwork the objective was to obtain a smooth surface rather than make a metallurgical match with the substrate; just a matter of stopping the seals wearing and hence oil piddling out.
Mark asked
How hot do you have to get the hook for the metal to bond?
Nothing much above room temperature.
Eug