SidecarFlip
Well-Known Member
Most reloading dies will have visible runout (of the decap rod) and expander ball, when seated securely in the die.
It will be very evident to to your eye if you rotate the die in your fingers while looking inside the bottom and observing the relationship of the decap pin / expander ball to the walls of the die itself, some will be real evident some will be more subtle, but 90 percent will show some runout (not staying centered in the bir bore as the die is rotated,
Thats what causes the expander ball to expand the mouth in a non concentric manner.
There is a cure (if you are determined to leave the expander ball in place.
I have to give John Whidden due credit for the the cure and it's a simple one. Just add an 'O' ring under the top cap of the expander ball where it threads into the die body. That alows the stem/ball to overcome any runout and allows it to center in the pore, as it contacts the case mouth during resizing.
neat and simple idea... Thanks John for your insight.
It will be very evident to to your eye if you rotate the die in your fingers while looking inside the bottom and observing the relationship of the decap pin / expander ball to the walls of the die itself, some will be real evident some will be more subtle, but 90 percent will show some runout (not staying centered in the bir bore as the die is rotated,
Thats what causes the expander ball to expand the mouth in a non concentric manner.
There is a cure (if you are determined to leave the expander ball in place.
I have to give John Whidden due credit for the the cure and it's a simple one. Just add an 'O' ring under the top cap of the expander ball where it threads into the die body. That alows the stem/ball to overcome any runout and allows it to center in the pore, as it contacts the case mouth during resizing.
neat and simple idea... Thanks John for your insight.
