I checked the vent again, by sticking a 1/16" drill bit in the hole, and that is what it is, as I just slipped it in by hand, and it would pass all of the way to the other side of the barrel, so it is clear.
I have not had a misfire since I switched to 3f for primer powder, and except for one failure to fire the pan of powder, and that was caused by a dirty flint, I believe. I hope to go hunting or at least find some time to shoot it some more, this weekend.
If it was mine, I would probaby take it out to a #51 at least, but I recond I will leave it alone since I intend to send it back.
I may get some 4f and see how that works, but for now, I am stuck with 3f.