The spacers allow the use of an a specific diameter expander to be used in a larger range of Caliber case lengths using that diameter bullet.
Without the Spacers NOE would need to machine three times as many expanders of different lengths with the same diameter. The website specifies the number (or lack of ) spacers for the case length of the caliber you are going to load for.
The Over_Travel ring is used for the Lee Auto Drum. Lee cautions about excessive travel of the case up into the expander die that could crush the plastic parts in the Auto Drum.
Dispense position Note: slider drop tube should not make contact with top of slot
The NOE website provides a cutaway image of each caliber that is listed using the diameter range of all the expanders. This image details the number and position of spacers used (if any), the placement of the over-travel ring and the stepped powder through expander.
The image also indicates the initial turns up of the expander die from contact with the bottom of the die and the shell plate.
Hope this helps.
Respectfully,
Tom Myers.
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