Instructions for making custom top punches


Resident Half Fast Machinist
1. Clean out the cavity to remove all the oil. I recommend using a cotton swab with dish detergent and warm water. This will not harm the O-ring. Remember to re-oil or otherwise protect the punch from rust when you're finished with the whole process.

2. Put the proper sizing die in your luber/sizer.

3. Stand a bullet up in the die. Note: Hollow point bullets should have the hollow point cavity filled up with hot melt glue or candle wax to form a smooth surface that is even with the edge of the hollow point cavity.

4. Put a thin layer of oil or grease on the nose of the bullet to prevent it from sticking to the filler compound.

5. Mix up your filler compound and fill the cup end of the punch. Be careful not to get any on the stem end of the punch. I have been using JB Weld® but other two part epoxies will also work fine. (Note: I have no financial or other interest in JB Weld®, but I am a satisfied user of the product.)

6. Insert the top punch in the ram and gently lower it down onto the nose of the bullet. Do not use excessive pressure or drop it on the bullet; you can generate enough hydraulic force to split open the cup. Lowering it gently allows the excess filler compound to escape without building up pressure.

7. Wipe off any excess glue from around the nose of the bullet.

8 After the compound sets up hard you can raise the ram and remove the top punch to let it cure. See the instructions that come with the epoxy you are using.

9. After curing you can use fine sandpaper or a fine cut file to remove any ragged edges around the end of the punch cavity. (I use very fine sandpaper on a rubber sanding block.) You are now ready to use your custom fit top punch just like any other top punch.

10. To prevent O-ring wear, keep a light coat of oil or grease on the stem area of the punch, and be sure to back out the set screw in the ram enough to prevent the point from touching the O-ring.