Are you saying you need to turn it inside out first, then twist it with the pipe wrenches to change the rate of twist, and then turn it inside in again?
Man, I was following all this right up to this point; but now I'm confused. I always thought that the shooter was able to determine the twist of a rifle by how much off-vertical he held it while shooting. You are suggesting that it can be done ahead of time? This is truly revolutionary thinking!