Originally Posted by buckbrush
Thanks for that link.
I don't understand why it's not consistant from case to case. Some are bad. Some are near perfect then there are those in the middle.
Well, point one from your original post is that ALL rifles will shoot concentric ammo better than ammo with runout, not just yours.
In terms of continuity of runout, there are variables, some of which you can control, others you cannot. You can get a bad batch of brass.
I have found that cases from Winchester, Remington, and Hornady tend to have more runout from the factory when new, v. Lapua, Norma, and Federal. Once fired cases have less to no runout than new.
In the case of sizing, if your case mouths have even as little as a thousandth or half thousandth of asymmetry, this can cause more runout when you seat the bullet.
Do this: measure the OD of a loaded round at the neck. Compare that to a sized case neck when using the expander, and also a sized case without the use of the expander. Then measure the OD of a fired case.....all at the mid-neck.
What are all of those measurements? If it is greater than 8-10 thousandths, that is a big problem. My Redding 270 die had 17 thousandths difference from a fired case to a sized case without expanding the neck over the button. Simply put, that is overworking your cases.
Plus you really need to buy a Sinclair concentricity gauge. Straight ammo is the only way to go.