Reloaders assume they are moving the shoulder back when they are sizing a case and then someone that has never put any thought into what was happing to the case when sizing told them they were moving the shoulder back.Originally Posted by milboltnut
Again, I form 30/06 cases to 8mm57 cases. There is .127" difference in the length of an 8mm57 case and a 30/06 case. It means nothing to those that never put any thought into it, but I did not move the shoulder back .127". The shoulder I formed on the 8mm57 is not the same shoulder I started with on the 30/06 case. No one has ever asked, "If the shoulder does not move back. where does it go? The 30/06 neck becomes part of the 8mm57 shoulder and part of the 30/06 shoulder becomes part 8mm57 case body. SO, when forming and or sizing the shoulder of the case moves forward and if the case last a long time all of that brass moving forward must be trimmed.
I took two 8x06 rifles to the rang, I fired 8mm57 ammo in both of the rifles. A reminder, there is .127" difference in length between the 8mm57 round and the 30/06 round between the datum to the case and head. After firing I found the shoulder of the 8mm57 had become part of the case body and the neck almost disappeared. I could ask, what does that mean?
F. Guffey
