He's a big BP fan and due to silliness on my part, I told him I was familiar with BP-guns myself.
Now that there is a pretty good chuckle
Psomniferum.
Just come clean and tell him you overstated your experience "a bit". I suspect as with most muzzle loader enthusiasts he'll be happy to help you along.
Here's a funny thought. He may be a member of this forum, or and unregistered lurker. So your cover may be blown anyway.