There are also two shapes for these punches, depending on the kind of insert used. Corbin offers both the ULD-TIP and the PIN POINT tip, which are similar in concept and design, but different in the specific ogive and length of bullets in which they are used. The ULD-TIP comes in two diameters or sizes, TIP-30 for the range of .284 to about .338, and the TIP-50 used in .338 to .510 diameter Ultra Low Drag ogive rifle bullets. There is some flexibility in selecting one tip or the other for the mid-range or transition calibers around .338, depending on how you want the bullet to look.
The other tip inset is the PIN POINT tip (TIP-45) which is designed with a 25-degree nose cone, and is for use with shorter bullets which need maximum BC for the caliber and weight within a constrained over-all length. Examples include the .450 Bushmaster in AR-15 platform, muzzle loader bullets, high powered large bore air rifle bullets in the 9mm to .510 range, and saboted or paper patched .45 bullets.
The rod portion of these punches can be replaced by means of a set screw. If a replacement is needed, ordering the insert rod, PUNCH-HI, is lower cost than ordering another complete punch.
Five parameters are required to get the right replacement punch:
- Type of punch (cavity forming or tip ejection): Specify T1 or T2.
- Type of insert (ULD-TIP or PIN POINT)
- Diameter of punch (usually similar to .157 or .161 and written on the die end).
- Sync length of punch to a given die cavity (written on the die, and original punch head). The punch insert rod is exactly 1 inch longer with 1 inch inside the punch head.
- Over-all length of punch from end of the punch head to end of punch diameter (also written on the die and original punch head).
The sync length refers to the specific die, so if you have more than one die even in the same caliber, it is very important to match the specific die to a set of punches. We set the length of the punches so that the first punch, which forms a cavity for the insert stem within the bullet core, is just right to reach into the die cavity a specific distance. Without the sync length numbers, we would be guessing how long to make the punch so it sits exactly where it should relative to the cavity depth and over-all die length of your die. The T2 punch length is not so critical. It just needs to be about the same as the original one so it can properly eject the finished bullet.
Below is the T1 punch (cavity forming) with the critical dimensions pointed out. Note that the tip length is NOT included in the over-all length or the sync length. Tip length is matched to the proper insert stem length and diameter, but can also be designed for making hollow point bullets.