Disappearing ejector marks

[winmagman]

I was breaking in a new barrel on my 6.5-284 this morning and checking pressure at the same time. I started with 45 grs. of Re22 with a 140 gr SMK and worked up in .5gr increments. At 46.5 I got a very slight ejector mark. so faint you had to hold the case just right in the sunlight to see it, the bolt opened just fine. At 47.0 grs I had the same thing. At 47.5grs.(Sierras listed max) no marks at all, and the cases continued to be fine all the way up to 51.0 grs. when the bolt started to get a little sticky.
Any body have any ideas what might have happened? I've only been reloading a couple of years and have never seen this before.
Thanks in advance
Chris

 

[Coyote Hunter]

I don't know....what exactly did happen anyway?
Confused!!

 

[doc76251]

Were you using unfired brass? Some times unfired brass is not quite "hardened" and will show signs similar to what you are describing on the first firing or two. If you were using a mixed bag that may be your answer. Otherwise.......ya' got me.

Cheers