I have some Rem And Win brass that I have Loaded up to 6 times. Since this is for a bolt I only neck size and bump the shoulder when needed. So far I have not felt a groove inside the case near the base to check for thin spots. I read that some people also measure the base diamiter to check for case expantion at that piont.( I understand the case shouldn't really expand here much) I have not checked this measurment in the begining so I have no idea how much case growth has occured here. Wouldn't I feel a groove inside the case base before the brass expanded to the piont of rupture at the case head? I trim my brass each loading, their isn't much growth at all in length if any. Do you guys measure base expantion on your brass? Will case failure come in other ways before excesive case expantion? Maybe I am to woried about this, I just don't like surprises. Thanks for any and all input.