The box the bullets came in.
I weighed all the bullets and separated out all the ones that weighed less than 165gr and all the ones that weighed 166 or more.
My thinking is that a too-light or too-heavy bullet might cause a failure to cycle correctly if my load is marginal, so if it works with the outliers I should be fine with more "normal" bullets.
My question is should I use the light ones to work up my loads, the heavy ones, or don't worry about it?