clocking a barrel

[Tobesan]

I have read about clocking a barrel so that the curve is up and down, as opposed to side to side and this makes sense to me. My question is how to determine the curvature and which way it's aligned. do you measure the amount out of concentricity at the muzzle?

 

[Bob3700]

With the bbl in the lathe, you make sure that the chamber and throat are running true. Then you can put a gauge pin in the muzzle and see where the high and low spots occur.

By taking material off the bbl shoulder, you can index the bbl to the action. Takes a bit more time but is worth it if you shoot 600 yds and beyond.

Before indexing bbls, you might have many minutes of windage differential between bbls that you screwed on the action.

For short range, I don't believe that it matters much.

Bob