I live in the South, we know what will rust a gun.
Oh yes! If you had a bore scope you would have an eye-opening experience as the moisture can get under the fouling and copper and cause metal corosion.....Interesting - I've never seen this happen.
It is not just the internet. The product was not designed for corrosion prevention or lubrication. Some folks still use it for that even if it is not very effective. This on the other hand works VERY well...Pretty much as far as the all knowing internet says.
Well I can say this.... I would love to compete against you. This is where experience and a bore scope (also knowing what you are looking at is a must) trump reading the rags or anything else.The first thing down your clean barrel is a high pressure dusting of carbon with vaporized copper suspended in the mix. Then your bullet runs the carbon heavy mixture over (what little amount sticks to the bore and isn't blasted out) and presses it into your barrel and coats it with a fine layer of copper. Each subsequent shot does the same thing with minor stripping of the copper as well as new deposition.
If that were not true you couldn't foul a bore to stability. After a few shots the amount deposited and the amount removed reach an equilibrium that may hold for hundreds of rounds before enough structure is formed to allow more build up than removal, at which point pressures spike (above the normal fouled bore increase over clean bore pressures) (according to at least one barrel maker) and accuracy degrades.
So you either keep carbon/copper blasting/plowing a clean bore or you keep carbon/copper blast/plowing a dirty one. Not sure which is harder on a bore, but figure either is acceptable considering barrel life.
Pressure is the one factor that I feel is most important. I suspect if you cleaned after every round, you could get more velocity out of a given barrel at the same pressure or less pressure with the same load. That might be worth the trade off depending on your circumstances.