Good video. However, as odd as it may seem, there is some evidence that copper fouling may not be as bad as was historically believed. Although it is a great idea to remove powder fouling, some research has found that as copper builds up in the barrel there comes a point where the next bullet traveling down the barrel will "scrape off" as much copper as it leaves behind. This I called copper equilibrium, and it may be the point where maximum accuracy is achieved. Before this point, as each round adds copper, the barrel conditions change and accuracy suffers.
I shoot a 35 year old slide action 30-06 and still get sub-MOA groups. Incidentally, my accuracy is limited by the shooter's ability, lol. My 66 year old eyes aren't as good as they used to be. Thanks for the information, keep it up.