Maybe you should not have cleaned them up . You should have sent them back. They are crap looking bullets . Were the seals on the box's intact ?
It appears to me that the cores were wet with something or some kind of contamination is inside or outside the bullet , old swage lube possibly but I have never seen it turn black like that . Possibly black mold growing on old swage lube . However they may still shoot ok as long as no imbalance is present but when you see that kind of presentation it does not give you much confidence .
Two box's will not break the bank but if that was a batch of 1000 I would be sending them back . It is a rare occurance and the vast majority of Berger stuff is good but every production line has it's failures at times.
However I think that is old stock as they seem dull but the label on the box is quoting a G7 BC so that label is not that old ?
I make my own bullets and I do a final wash with dilute sulfamic acid in warm water . It removes everything and leaves the bullets super shinny and clean and once they are properly dried , then ready for moly coating.
bsl135 ( " Bryan " might be Bryan Litz of Berger anyway so he should know ) may well be right it could be contamination in the final washing process . I can't see a bulk manufacturer using an expensive agent like Sulfamic Acid . I bet they are just using soapy water and not changing it often enough .
We get this kind of thing in Australia , they send out the second quality stuff to us. That is why I make my own now. New Mexico might be getting the same treatment as downunder. Many years ago I got six box's of Berger 55 grain 224 bullets sent out and 20% had split jackets at the ogive . Some never made it to the target . Might have been just bad luck but that was the catalyst to start making my own . I may not be able to match some of the accuracy of the specialised VLD stuff but If I do make a faulty bullet I can see that and not use it . It is not so bad when you can just take it back to your local gunshop but when you bring it in from overseas it is very dissapointing .
You still have to buy jackets and some batch's are not as good as others but I redraw any crook batch of jackets to true them up more .
This is what some of my 6mm bullets look like just incase you think I am all BS .