Author: britrifles
Subject: Case Neck Concentricity
Posted: July 10 2023 at 8:31am
Not sure what to suggest Michael. Lapua is generally very good brass. In the sample of .223 and .308 new cases I checked, neck runout measured less than .001 inches. And yes, I think if the neck is out of alignment going into the Lee Collet Die, it will come out that way too since only the neck is touched by the die.
Subject: Case Neck Concentricity
Posted: July 10 2023 at 8:31am
Not sure what to suggest Michael. Lapua is generally very good brass. In the sample of .223 and .308 new cases I checked, neck runout measured less than .001 inches. And yes, I think if the neck is out of alignment going into the Lee Collet Die, it will come out that way too since only the neck is touched by the die.
I found that my DCRA Long Branch barrel chamber neck is slightly off center with the axis of case body. A new case measuring zero runout comes out after being fired at .001 inches. All the fired cases measured .001. So, neck sizing these in the Lee Collet Die also gave .001 neck runout. I think this is still very good, and nothing to worry about.
My conclusions so far shooting the No. 4 .303 and 7.62 is that bullet runout as much as .006 is completely undetectable in the 7.62 out to 1000 yds and as much as .010 in the .303 was not detectable at 200 yards on the target. .010 however on my .223 at 600 yards was a definite problem for me and the Wilson dies solved that for me.
Check the neck runout on some of your fired cases, if the neck of the chamber is concentric with the body area, the runout should be less than .001, since the fire formed cases should be the shape of the chamber (with a slight bit of spring back).