I am measuring .008 case stretch before, vs. after, firing. (full length sized brass) I am also showing flattened, and cratered, primers with mild, in the book, loads. (just over bottom of the book) Bullets seated .020 off lands.

All brass is clean and dry , chamber is dry. (No lube, solvent, or oil) I am thinking .008 is a bit excessive, and probably what is causing my flattened primers. First thought is to get some new brass, fire form, and neck size only after that. My other thought, is to have the barrel reset, but I also have a short throat. (90 grain sierra HPBT loaded to book length show moderate land marks on bare bullets.) I can feel contact before closing the bolt down.

When loaded against the lands, primers don't show nearly as much flattening.

I wanted to know what your thoughts are on my problem, and possible solutions.