Line on case below shoulder

[Tmm01]

Here are the details: 6.5 creedmoor Alpha brass, 12 firings, Proof barrel, the line is only on the brass that has been sized. I have 50 more that have been fired but not sized yet, they don't have the line. I inspected the sizing die (Forster) it looks perfect. These have been shoulder bumped .002 when sized. Is it the very beginning of a separation in the making? Case head separation being more common, but this looks suspicious, even if the interior of the case doesn't look out of place.

 

[justin amateur]

Y'er case chamfering tool is rubbing on the exterior of y'er brass.
Place the chamfering tool on y'er brass,
look at where the contact point is on the bottom edge.
Touches right at the visible ring on the brass.
Bottom edge of tool and brass rotation equals bright line.

 

[Tmm01]

Y'er case chamfering tool is rubbing on the exterior of y'er brass.
Place the chamfering tool on y'er brass,
look at where the contact point is on the bottom edge.
Touches right at the visible ring on the brass.
Bottom edge of tool and brass rotation equals bright line.

I checked, but that isn't it, this just popped up on the last batch of cases I processed.

 

[Rocketmandb]

So, this occurs after firing, cleaning and sizing? Or is it occurring after firing and only on certain cases that have been previously sized?

 

[Rocketmandb]

Also, is it just a mark? Or can you feel it if you run your fingernail over it?

EDIT: Did this only happen after the 12th firing? Or has this been happening since it was first sized after the first firing?

 

[Tmm01]

So, this occurs after firing, cleaning and sizing? Or is it occurring after firing and only on certain cases that have been previously sized?

It has only just shown up after sizing this last batch. I still have some cases on the same number of firings, but they haven't been processed (cleaned, sized, annealed) and they don't have the line.

 

[Rocketmandb]

It has only just shown up after sizing this last batch. I still have some cases on the same number of firings, but they haven't been processed (cleaned, sized, annealed) and they don't have the line.

Is it on all cases or just a few?

 

[Tmm01]

Is it on all cases or just a few?

They all have it, but it is a bit more pronounced on some.

 

[Tmm01]

Also, is it just a mark? Or can you feel it if you run your fingernail over it?

EDIT: Did this only happen after the 12th firing? Or has this been happening since it was first sized after the first firing?

This just happened after the 12th firing and them being processed, I have 50 more that have been fired but not processed and they are fine.

 

[Rocketmandb]

This mark is likely not due to something like a sizing die where the case is going in, then coming out. Something that would cause the mark would scrape, this one looks cut. This means that it's occurring during rotation - either the case rotating, or the tool rotating.

At what stage of the process do you notice it?

 

[Tmm01]

My buddy just called me and told me to check my Little Crow trimmer, that lines up perfectly....LOL I have it set-up a little different, more of an angle and that appears to be the cause. Thanks for everyone's help, this was driving me crazy.