July 25th 2023Here is a simple task that you can do to make your seater die fit your match bullets better. You can lap the stem of the seater so that it matches exactly the profile of the bullet. This allows the seating force to be spread over a greater area of the jacket. This allows for a smoother, more consistent seat, without dents, creases or sharp rings on your bullets. Erik Cortina, of Team Lapua-Brux-Borden, demonstrates this process. Erik, a top F-Class shooter and skilled machinist in the country, explains, “Here, I’m lapping a new seater stem with lapping compounds. I put a bullet into the lathe, and then lap the inside of my seating stem. I applied lapping compound to the bullet as well as the stem. You can do this with a hand-drill and bore paste. In the picture below, you can see how much contact the stem has with the bullet after it’s been lapped. This bullet is a Berger Hybrid 7mm 180-grain. “Q1: Are Seating Stems Lapped Really Necessary? It can be helpful, but it is not necessary to make the seating stem match a bullet exactly, especially if you are loading hunting or varmint ammunition. It is useful to polish the stem internally. This should remove any ring or dent that forms on the jacket of the bullet during seating.Q2: Are there any downsides to this process?Not really. If you shoot a variety of bullets for a cartridge, you might not want to conform your stem to resemble a specific bullet. Leave it alone. Lightly lap the stem’s inside to remove burrs/sharp corners. This will prevent the formation of a ring when seating bullets.
Photo credit Sierra Bullets
Similar Posts:Tags: Bullet Seating, Erik Cortina, Lapping Seating Stem, Polish Die Stem, Reloading, Seating Die, Seating Stem
