I've shot CoreLokts in my .243 since 1980...

I always take the first two bullets out of the box and shoot them to make sure THAT box shoots were it should...I then write the date on the back of the box and how high it shot at 100 yards...I typically sight in 2-2 1/2 inches high at 100 yards...

This way, if I'm using the same box 3 years later and want to recheck my zero, I have a record of where THAT box shot...

You can buy the same loading and lot numbers but sometimes there will be a difference in where they land on the target...