corbin et-1-r User Guide

ET-1-R Jacket Trim Die

The ET-1-R jacket trim die fits a standard 7/8-14 reloading press with slotted ram (for

standard RCBS type button shell holders). You can use it to trim a given caliber of bullet

jacket to shorter lengths. The length of the trimmed jacket is adjustable over a wide range

by turning the threaded stop in the top of the die.

A tapered, piloted punch slips into the reloading press ram slot, just like a shell holder.

Do not try to use a shell holder in addition! It will not fit the punch base.

A simple length setting gauge is provided with the die, to help you set the threaded stop

for the desired length of jacket. Determine the length you want, and then set the sliding

collar on the gauge so that one end of the rod is exactly this length. Hold this end of the

rod up into the die, and adjust the threaded stop in the top of the die so

that the collar just touches the die face.

A lock nut on top of the die secures this setting. You can tighten it by
hand or use light pressure from an end-wrench (pliers are not recom-

mended, as they can slip and mar the die holder, stop screw threads or

the lock nut).

Screw the die into the press top one or two full turns only. Put the punch

into the ram slot. Raise the ram all the way to the top. The punch should not

contact the die face yet. With the ram all the way up, lower the die (screw it
down, clockwise) until the die mouth just touches the punch. You may need to slightly increase the amount
of contact while trimming the first jacket, so do not lock the die lockrings yet.

Wipe the tip of the tapered punch lightly with Corbin Swage Lube, and do the same to the outside of the
bullet jacket. Place the jacket mouth over the pilot (projecting tip) and raise the ram so that the jacket
enters the die. With the die properly adjusted, the punch will just force the jacket to be cut off on the
sharp die mouth and will not be pushed into the die mouth. If the die is set too close to the ram, the punch
may be damaged or the edge of the die may be chipped or rolled over from the high pressure. Always
set the die carefully so that, at the end of the press stroke, the ram just barely makes the punch touch the
die mouth. This leaves no room for the jacket, and thus pinch-trims it off. If the jacket is not pinched
through, or at the least, cut through enough so that the jacket and trimmed section can be separated
easily with light finger pressure, lower the die very carefully in small, 1/8-turn increments.

The jacket will spread over the tapered punch and split, so that the ring of metal that is trimmed off the
jacket either falls off by itself or is expanded so it can be easily pushed off with your finger. Do not
allow cut pieces of jacket to remain on the punch, or they may interfere with the operation.

To eject the trimmed jacket, use a small plastic or wooden mallet and tap on the plunger (ejector rod) at
the top of the die. The jacket will be driven out. Be careful not to cut yourself on the sharp jacket edge
when ejecting the jacket! Let the jacket fall into your hand rather than trying to grasp it as it emerges.

If a jacket will not fit over the pilot (projecting tip on the punch), then it has walls too thick to be trimmed
with this procedure. The pilot must fit inside the jacket. Otherwise damage may occur.