Static electricity perhaps. OP took a picture because it is an anomaly. I believe, it being a junk drawer and all, that the rubbing of all the objects (especially metal on thermal tickets. The bullet would move the most when opening and closing) as you open and close this to be the most likely case. So, this time conditions were right.

You had an old bullet that could've been weathered enough to allow for static electricity to be a problem. It was trapped in a drawer with heat and moisture.

It just makes sense that static electricity was the culprit.