In your opinions fellows.....does not being able to seat the PRB at the same depth according to your ramrod marking stem from fouling buildup on the face of the breech or possibly on the sides of the bore as well??
Hawken, that is a great question. It has happened to me a few times on very humid days in the past and I've had to tap the ramrod down with the back side of my hawk...
I can't say for certain, but I've always thought it to be on the sides of the bore - only because I was able to tap the ramrod down to its mark. It didn't take a lot of tapping - but it was being stubborn enough not wanting to seat without the tapping.