This fella has an interesting method of straightening runout.
He taps it instead of pushing the neck like the Hornady does.
And according to this guy, who is a top shooter in the US it works, but his invention is like 390 USD. But the fella using the tire guage is using the same principal.
Have a look and the video of the top shooter's invention is about halfway down.
http://forum.accurateshooter.com/thr...-tool.3927609/
Expensive way.
http://premieraccuracy.com/index.html