Bit of a joke here at the expense of a mate who has no sense of humour.
We were talking random junk about shooting and him maybe building a .223 target rifle. He liked a few things but some had slower twists that wouldn't be suitable.
I said "I just left my in the sun to heat it up then twisted the hot barrel to increase the rifling twist inside."
He looked at me half comprehending for a moments before stuttering out "Oh yeah? How, um... I could do that....."