Dick I'm still digging into this but I'm not convinced it's Joseph. It's late, 1820s or 1830s maybe, and Joseph was 'up the river' by that point I believe. I know he was up in Milton, also Lewisburg when his son Gideon died. This has some upper Susquehanna characteristics and I'm wondering if perhaps this may be an early Gideon Angstadt. He was born in 1800 I believe and to date I have yet to see a piece *signed* by Gideon Angstadt. Joseph, on the other hand, did sign his work. Maybe not all, but there sure are some signed pieces. This actually looks better than most of Joseph's work. So I guess it might be a late Joseph, and probably not made in Berks but rather somewhere up in Northumberland, or it may be a Gideon Angstadt.
I think there have been a number of wacky rifles attributed to Gideon Angstadt but none are signed and when one tried to dig down as to why the attribution, it completely falls apart. Again, I've yet to see one with a signature. And he was dead by I think @ 1852 or within a couple of years either way (off the top of my head at the moment).
Another very interesting thing here is this: just look at the rifle without the carving or decoration. Architecturally, it's actually almost a ringer for one of the earlier Peters, especially with that long low cheek. And with no lower butt molding, there's no weird step.
I don;t know but I',m still looking into this. Hopefully Dave M or Noel may have some thoughts. I can;t see it as anything but a prototypical 'up the river' rifle.