I read that post a couple of weeks ago., then just went thru it again. Personally I have a few old cannons and with my 15 or 20 shots a year I havent found them to be a problem .
I am not trying to dispute this issue. What I am saying is perhaps its not necessary in all cannon applications.
For example a group of re-enactors with a large bore seeing regular usage would be better off with more dollars in thier barrel than say the casual summer time shooter.
Sure a seam will rust .,so will any mild steel., anywhere on it., it will pitt and rust. I swab my bores with oil.,and let age take its course.
I own Richs Rooter Service., 23 years Lots of sluge acids.,sulphuric and others ., film developer., on and on., I deal with seamed pipes daily. Some actually might call me a pipe expert. I see what differant products do to differant types of pipe., and I see it new and old.
I am very happy with my new Grey-Star Pipes and believe they will provide years of sitin around and a few shots a year.