Cross posted from another thread
How to use the Hosford gauge
Part 1
https://www.youtube.com/watch?v=1jQZn4kohH4
Part 2
https://www.youtube.com/watch?v=sfBP7a0TbjM
Henry gauge. The short metal piece is .038" to confirm the gauge.
The barrels are secured to a weighted box with bungie cords
I affixed a tape measure so the rule is not needed