Of course, there's Damascus and then there's Damascus. With shotguns there are Damascus barrel guns (as well as a bunch of fluid steel guns) I wouldn't shoot on a bet. There are also several in my closet that I shoot all the time with both black and low pressure smokeless with no worries whatsoever.

The Damascus rifles I have had have all been of decent quality and in decent shape. Mostly they get fed BP 'cause I like the mess, but I don't hesitate to feed them N-f-B smokeless loads except for the noxious chemicals needed to clean that nitro stuff out of the barrels afterwards.