FWIW, (and not at all to attempt to diminish your experience) We had a Issac Haines style fullstock 50cal. with a swamped barrel that got an honest 2500 rounds through it (knew the count by the RB bought) that my wife shot in BP competition. She didnt use a bore guide, but did use a 'poly' range rod and the muzzle rifling didnt look to have worn (we do not have a borescope) and the thing would still shoot possibles if the shooter could. She had a new custom caplock made and retired the first one, then a good friend expressed a desire for it, so he shoots it now. Maybe it was the barrel steel used as I have seen old soft barreled originals that were nigh onto smoothbores. A couple of friends even got that special spud to 'cone' their barrels to be able to thumb seat a patched RB sans short starter and they determined it did not affect the scores when they shot paper. The coning does uniformly remove the rifling in a taper, but I digress.
But 'careful is as careful does' (apologies to Forrest Gump) and I usually use a bore guide as I have them and it 'seems to be logical'. I dont surgically clean my barrels like some do either. My 100ish year old Stevens 22LR target rifle is still competitive, even if I am not anymore, same with My Martini MKIII International, and I would probably cringe to see what a borescope would show me, then there would go the 'confidence in my equipment'.........Having some knowledge of metals I find it hard to believe that a brass or aluminum rod will damage a rifle barrel steel.
So use 'em if ya got 'em, get 'em if ya dont, but dont get too anal about not having one now and then (and dont hamhandedly slam rods and jags through a bore). These things will likely outlast most of us; I know several of mine through the years have served a couple of generations of shooters and are still going strong.
