Rotating your cases during bullet seating can reduce run-out

April 28th 2022. Here’s a simple technique to help you load straighter ammunition with less run-out (as measured by the bullet). This process is free and takes only a few seconds to load a cartridge. When you next load ammo using a threaded (screw in) seating die, consider seating the bullet in two stages. Place the cartridge in the seating die so that it is only half-way up. Lower the cartridge and turn it 180 degrees. In the shell-holder. Now, place the cartridge in the shell-holder. Steve’s 30BR cartridges were coming out of his neck-sizer in good concentricity. However, the run-out almost doubled when he seated them. Steve tried rotating his cartridge while seated his bullet at the suggestion of other Forum members. Steve measured the run-out of his loaded rounds. Surprised, he noticed a significant reduction in runout for cases that had been rotated during seating. Steve explains that he loaded the rounds yesterday by seated the bullet halfway, turning the round 180 degrees, then seated the bullet. This reduced the bullet runout by nearly half compared to the first test. “Steve measured the runout of his 30 BR brass using both the one-pass (with 180) and two-stage (with 180). rotation) method. The two charts below show Steve’s measurements. As you can see, there was less run-out for rounds that were rotated during seating. The change is very small (less than 0.001). However, every little bit helps with accuracy. This two-stage bullet-seating process is recommended for those who use threaded (screw in) seating dies. Rotating your case during the seating process will not cost you anything and may produce straighter ammo (although nothing is certain). If you don’t see any improvement in the target, you can always return to seating your bullets in one go. READ Forum Thread.
Similar Posts:Tags: 30 BR, Case Run-out, Concentricity, Dies, Hand Die, Reloading, Rotate Seating Die