Savage had no answers, other than to try a different lot of Hornady ammo. This time there was no keyholing, even though I was using the same box of ammo as when the problem occurred. The only difference was the temperature. It was cold when the keyholing occurred, about 8 degrees F the first day and in the teens the next day. During the latest session it was in the low 50's. Any suggestions of why cold temps would create a problem?