A couple years and 7,000 downloads later, I think I figured out why the same load in the .243 Turkish Mauser kept getting worse:

1) pinched bullets from 308 brass necked down

2) copper fouling in the throat.



The barrel is an Addams and Bennet blank, and it is as rough as any bore I have ever seen.













And now I know why the guy from Hodgdon was only able to get detonation outside the lab with a rough throated .243:

He had copper fouling too.





And that is why the FBI could not get two bullets in a row to match from the Rem700 30-06 that shot Martin Luthar King:

Copper fouling.