Lee;
Sounds like you found a keeper. Rodda's are nice
rifles. I have owned, at times, 4 of them. Still have one.
Here is some info. to get started on;
www.internetgunclub.com has a good bit of info. on Rodda.
You will have to register, if you aren't already, to get
the info.
An ebay seller; cornell military pubs has a reprint
of a 1929-30 Rodda catalog for $15.00 or so. I have seen
a copy and there is not much new info.
Lewis Drake has a Rodda catalog reprint for sale for
$17 that is from the early 1900's. I have not seen this
one, but a copy is on the way so whenever it shows up I'll
let you know if there is anything new in it. You might also
do a search on gunshop.com forums. a couple of years ago
there was a long thread on Rodda, the surviving family
and some good info. on who made some of their rifles.
As far as shotguns go, I have never seen a double
breechloader, just a SxS 14 bore muzzleloader from about
1855 or so.
Good Luck
Raff