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Punch, PF EXT FMJ base-rolling
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Quantity in Basket:
None
Catalog No.: PUNCH-HM
Price: $70.00
Shipping Weight: 0.50 pounds
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This is an external point forming punch, made with a concave face, to help put a nice even fold on the open base style FMJ bullet. You can make FMJ stype bullets with any standard open tip 3-die set, or actually, just by seating the core in the jacket while the jacket is placed backward or solid end first into the PF die.
The core seating punch is used to put a core into the jacket and shape it into the bullet shape with just the point form die. The lead core must come close to filling the jacket but leave enough jacked unfilled to form over part of the core at the base. When the core is seated, and the full metal jacket nose created, the base is just a straight cylinder with a short section unfilled by the core. If you shot this bullet, it would tend to flar out at the base as soon as the bullet was just leaving the barrel. Gas pressure inside the open tubular base section would expand it and cause poor accuracy and higher drag.
To solve this problem, the base is rolled over so the muzzle gas pressure pushing on the outside surface will help keep the base from expanding. To get the open base to "roll over", eject the bullet, turn it end for end, and push it gently back into the point forming die. You can use the base turning FMJ punch for this. Push the bullet into the die far enough to start a partial nose curve on the base. Just get the edge rolled around a small amount. Then eject and flip the bullet end for end, and push it back into the die more firmly using this base rolling punch. Now the base will have a clean and even fold so gas perssuer at the muzzle will help hold the base closed instead of peeling it open. Finally, press on the base with a regular flat base point form punch. This completes the base with an even fold.
Note that if the base wrinkles or won't close fully flat, the core length is incorrect for the jacket length. You can make lighter bullets in the same jacket by dropping a "bullet ball" into the jacket and seating the core on top of it. This take up space inside the jacket but barely adds any weight.
This illustrates the seating of the core into the jacket using the point form die, then pushing the bullet backward into the PF die to put a taper on the open end, and finally using the PUNCH-HM to evenly fold over the base (followed by using a regular flat punch, not shown, to finish the base).
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