Case head separation

[thane]

I was shooting my 6mmbr yesterday loaded with some 70 gr BK bullets.
The group was looking pretty good until the 4th shot went 1.5" high.
Upon retracting the case, the bolt was a hard lift and would not extract
the case until I tapped the bolt handle. The bolt came back with only the
base of the case! The remainder of the case was stuck in the chamber.
This ended my shooting for the day.
To make a long story short, after investigating it was discovered that as these brass were just shoulder bumped and that the head space was 0.007"-0.008"!
Not sure how it has come to this but yes, I should be checking this every time. :-[
Now, I guess my question is, can I load some longer bullets engaging the lands to ensure the bolt face is contacting in order to safely blow back the shoulder?

 

[BoydAllen]

You generally don't get a head separation on the first instance of over bumping, so you probably have done the same thing more than once to your cases. I would look for a bright ring above the head and straighten a paper clip and then put a 1/8" 90 degree bend in the end and use it to feel for a groove on the inside of each case near the head. that would be what is called an incipient separation. If you have been sizing all of your brass the same way, you probably need to toss it, just to be safe.