http://www.leeprecision.com/cgi-data/instruct/RM3512.pdf"
ADJUSTMENT FOR LEE PRESSES Screw the die in until it contacts the shell holder, plus one turn more. Run a case into the die. You will feel the primer being extracted, then the lever will come to an abrupt stop. At this point, the lever must be pushed firmly (min 25 lbs.) to close the collet and size the neck. Extra bullet grip may be obtained by screwing the die in an additional quarter-turn.
Other brands of presses that toggle or snap over at the end of the stroke provide no feel and can damage the collet neck sizing die if adjusted as above. We suggest the die be screwed in until the die contacts the shell holder, plus
2 FULL TURNS This will prevent the press from toggling over center and give the operator feel of the collet closing.
OPTION Even greater accuracy can be obtained by rotating the case one-half turn and sizing the case a second time."
The collets are squeezing brass onto an stell mandrel and only so much force is needed. It would not matter if you put 30 pounds or 100 pounds downward force on the lever, the brass will not compress and neither will the mandrel. All you are doing is putting extra stress on your die and your press. The cap is aluminum and they will pop (don't ask me how I know
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If you adjust it per instructions the press will not come close to toggling over. By raising the lock nut and thus the lever, you are operating the same, just at a more comfortable position.