Bullet Reducing Die
FROM ____________ TO ____________
BRD-1 -R
-M
-H
OPERATION:
Lubricate the bullet by wiping with fingers moistened with Corbin Swage
Lube. Place the bullet on top of the punch. Raise the ram to the top. Screw the
die down until it contacts the bullet. Lower the ram slightly, and screw the die
down a little at a time until the bullet fits far enough into the die so it moves
freely. Short bullets may not emerge entirely from the die at this point, but they
should be past the constriction in the die.
The Corbin Bullet Reducing Die draws
down (reduces) the diameter of a bullet
by pushing it through a die and out the
top. The punch presses on the BASE of
the bullet, and should match the base di-
ameter and shape of the finished (drawn)
bullet. If a punch is used that is too small
or the wrong shape for the base, it will
deform the bullet resulting in poor accu-
racy.
Bullets can usually be reduced at least
0.005-in diameter, depending on the ma-
terial strength and thickness of the jacket
walls. It is possible to reduce .357 pistol
bullets to make .355 (9mm). It is also possible in most cases to reduce a .323
rifle bullet to .318 even though this is .006 inches.
Some bullets will curve or extrude too much lead core from the open end
when they are drawn down. All bullets will do this if drawn down far enough.
It is usually better to make the bullet by swaging rather than reducing an
existing bullet. But in cases where the draw is less than .005 inches, the poten-
tial accuracy of the bullet is not damaged enough to matter for practical pur-
poses.
The die screws into the head of the
press, replacing the floating punch
holder in Corbin swaging presses. It has
a 7/8 X 14 thread for types -R, -M, or -
S, or 1-1/2 X 12 for type -H. The punch
fits into the press ram. In type -R die
sets, the punch fits the shell holder slot
of the reloading press (without a shell
holder present). In type -M and -H sets,
the punch screws directly into the press
ram like a swaging die.
The die should NOT be run down all the way and then the bullet pushed up into
it, because this would not use the full leverage of the press. When the press is
adjusted correctly, you can use rather mild pressure on the handle of the press
and the bullet will draw with little effort.
A lock ring is not normally used on the draw die, because if it is allowed to float
slightly in the threads of the press, it can align better with the punch and make
the bullet go through more evenly drawn.
If the die is less the two full turns (threads) in the press head, do not attempt to
draw with that setting. It is important to have at least two full threads engaged
to avoid putting too much pressure on too few threads, which can cause thread
damage.
The bullets may not emerge until you have drawn two or three of them. With
some diameters and lengths, the bullet can pop out with a sudden rush, per-
haps flying out the top of the die with some force. Therefore, do NOT look
down into the die or place any part of your face near the top of the die while
drawing.
Each draw die is designed to use a certain range of length, diameter, and wall
thickness, and may not work or could even be broken if an attempt is made to
draw other materials. The only bullet guaranteed to come out the correct
diameter is the sample bullet used to adjust and test the die. If you did not send
at least ten sample bullets with the order, then a stock bullet had to be used.
Because jacket and core materials may vary in hardness, thickness, temper,
and alloy from type, brand, and lot, pushing a different bullet through the same
die usually results in differences in finished diameter. Therefore, it is extremely
important that you send sample bullets and use the same exact type, brand and
lot if you expect the diameter to be precisely as ordered. Variations as much as
.0015 inches can occur with changes in brand alone.
Bullets are always more accurately swaged from internal pressure than re-
duced by external pressure: for best accuracy, use Corbin Bullet Swaging
equipment. However, for draws of less than .005 inches, acceptable accuracy
is usually obtained. Draws of .002 or less inches cause no noticable change in
performance.
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