Collet Die Adjustment

If you are using the Collet die in an RCBS Rockchucker press, or a similar design that toggles over center at the top of the (ram) stroke, this applies far greater force than is necessary to resize just the neck of the case, and can damage the die or collapse the case. To correct this situation, adjust the die two full turns into the press after the die contacts the shell holder with the ram at the top of its stroke, rather than one as in the instructions. This will stop the press before it gets to the toggle over point. With a press without having an over center feature, apply about 25 lbs. of pressure to the handle once it bottoms out to resize the case. On most presses, this translates to over 600 lbs of pressure on the ram.

The collet might be stuck in the closed position from closing the die without a case inside. Remove the cap from the top of the Collet die and push the mandrel, collet sleeve and collet out through the top of the die. Open the collet back up with a tapered punch or Phillips screwdriver.

If this occurs with a full length sizing die, the decapper/expander is out of adjustment. The decapper/expander should be flush with the top of the decapper clamp. If it protrudes more than 1/4 inch, the die will be resizing the inside and outside diameter of the case neck at the same time, resulting in a collapsed case shoulder.