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RBT starter/core seat die, type -S
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Quantity in Basket:
None
Catalog No.: BT-1-S
Price: $249.00
Shipping Weight: 0.50 pounds
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This is the first half of the two-die RBT-2-S set, used to
seat the lead core into a jacket and form an angle on the
bullet base, in preparation for finishing the RBT base in
the BT-2 die.
Bullet jackets are typically flat base when you make or buy
them. The pressure of seating the lead core into the .001-
.002 inch undersized jacket, and expanding it in diameter,
also can be used to reshape the flat base into an angled
boattail shape (which lowers the drag and increases the
BC or ballistic coefficient of the bullet).
The BT-1 die replaces the usual CS-1-S core seater. You
do not need to seat the core first, and in fact, that will
cause problems with getting the jacket into the BT-1 die.
Put the loose core and jacket directly into the BT-1 die,
and seat the core using the appropriate diameter core
seating punch (which must fit the ID of the jacket at
the particular length of core you choose, for a given
weight of bullet).
You can tell when you have used enough pressure, because
the base of the flat jacket will become a sort of truncated
conical shape, providing an angled base section that uniform
and well defined. The base left on the end of the jacket
should be the same diameter as the ejection punch (internal
punch, which fits into the threaded end of the die and
stays internal or inside the die and ram during the entire
operation).
This die is sold separately as a replacement, not as a
stand alone product. While it will make a conventional
boattail shape on the base, you will need to use a punch
with a similar shape of cavity to push it into the point
form die and make the ogive. If you do this without
first completing the RBT base in the BT-2 die, the punch
edges will automatically form a less than perfect
step or rebate that will vary with the amount of pressure
it takes to form the ogive on a given jacket. It is far
better to pre-form the RBT base exactly, using a second
die, than to get variable rebate step shapes depending on
pressure, jacket hardness and thickness, core ductility, amount
of lube used, shape of ogive, and other sometimes changing
factors. That is why we sell the RBT set as a two-die
package with a matching base punch for the point forming
die. It is precise, consistent, accurate, and it works!
The die set comes with an internal punch (ejector), and
an external punch which is a core seating punch. It is
usually (by default) the size and shape for a standard
open tip bullet in a commercial jacket, but the diameter
has to fit the ID of your jacket. If you do not know
the diameter that you need, you can use the "note" to let
us know which jacket you are using and about how far down
into the jacket you will be seating the core. Then we can
estimate the required punch diameter, or contact you if
we need sample jackets or more info.
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