Yesterday I shot my first block of home loads and today I'm noticing some weird marks on the case neck, right at the top where the bullet sits. They're 6 equally spaced crimp type marks, looks a lot like the rifling being stamped on them.
My loads weren't excessive, 43.0 - 45.0 grains of Vhit N140 in 0.5 grain increments. These are .308 using Sierra 150grn heads (#2125). Cases were trimmed to 2.008" and bullet seated to an OAL of 2.750"
Any ideas what's happening, and more important is this normal and are the cases ok to reload again. I've attached a photo but not sure how clear it is.