Re: Full length resizing of Magnums
Measure it. It is so simple to measure the twist and it gives you the right answer for your rifle, which is the only one that matters.
Put a patch on a jag, start it into the rifling just past the throat. Put a masking tape tag on the cleaning rod pointing up. Measure the distance from the tag to something - I use the end of my bore guide that sticks back out of the action. Push the rod in till the tape has made one turn and is pointing back up. Make a measurement from the tag to the same place. Subtract the two measurements. There is your answer.