Forrest,
Would the finely ground tungston in Nice Shot or Kent TM (KTM), both having very soft pellets, scratch a damascus or early fluid steel barrel or would it slowly polish it? I've got a couple old Parkers that could use a little barrel polishing!
All kidding aside, you make a good point but I wonder how many shots using an unprotected shot column could be shot before any measurable difference in a bore could be measured?
Mark