It looks like it may have been an area of deep pitting that someone tried to grind out with a Dremel stone. Hopefully I'm wrong.
Finding corrosion in that area is not unusual when stripping for recoloring barrels, and sometimes when you remove it you find deep pitting.
I'd try to get an accurate wall thickness measurement in that area. If very thin, you may be able to have the area built back up by having someone TIG weld it.
Since there is color in the area, the tubes may have been recolored after whatever was done to it.
Regards
Ken
Last edited by Ken61; 05/02/17 07:15 AM.
