OIS, other range rats, I was at the range yesterday with the muzzleloader. I loaded my trusted 300g hornady xtp with 90g 777 2F loose. I have only read about the term but I think they were key holes. Can anyone tell me what causes this? The temps were already in the 70s in early morning and humidy has been climbing lately. This is my standby load and has never happened before.....any thoughts?