So somebody said they had rust in their bore from shooting Pyrodex? Since my rifles have each shot dozens or some hundreds of rounds with Pyrodex and Triple 7, I decided to closely inspect my bores. I have close copies of orginal rifles I built, and these have been fired hundreds and some thousands of times. They are a .40 Thomas Oldham Bedford caplock, a .40 Jacob Wigle flint, a .45 Green River Rifle Works Leman caplock (I built it in their shop), the two .50 flinters pictured in this thread, a .54 Leman and a .54 Bridger Hawken caplock (also pictured in Percussion forum currently, "scaled down Hawken type rifles"), and a .58 fullstock Hawken flintlock.
I looked down the bores with a Streamlight Stylus LED light (got mine at Radio Shack for about $15). You can see the breech plug. Then I wiped the dust out of the bores and looked again. Some had a dark ring at the corner of the barrel and breech plug, so I made breech plug scrapers to clean that out. Used a piece of 10x32 bolt 3/4" long to thread into my cleaning rod, cut a notch in a piece of flat brass and soldered this over the end of the bolt, and filed it to just slip down the bore, square and sharp. Scraped the fouling out. Soaked the lower bore with my bore cleaner, dried it out, then cleaned the bores with JB bore paste and wiped clean. All bores were bright and clean with no rusting or pitting. I oiled all the bores again. So that is my personal experience with this bore rusting issue.
