Excellent contribution and information on all fronts. But let me preface the following by saying that for now I don't have any additonal info on Eduard Wundhamer.
The engraving is very similar to what one would see on a Franz Neuber of Wiener Neustadt(location of an armoury) or Peterlongo, and possibly Josef Kugler, of Innsbruck in the Tirol/Tyrol(
http://en.wikipedia.org/wiki/State_of_Tyrol ) region circa 1900. Also I’m curious if your locks have an extension at the butt end of the lock, which appears to be for stability. It’s usually apparent by a slot, which is a circular cut near the end of the lock and is disguised by engraving. Many examples are O/U versions for combos or double rifles(probably easier to regulate) and at least the tubes were soured from Suhl. But yours is earlier with higher end pattern welded tubes that were sourced from Belgium instead of fluid steel usually by Krupp. If Richard Mahrholdt was active in the late 1800s, he could have been the Suhl connection for Peterlong as a Mahrholdt was a member of Suhler Waffengesellschaft(Suhl Weapons Company) Wittwer, Schemmer & Mahrholdt in the 1920s and early 1930s. The circumstances of the depression may have forced the firm to close. Also in the early to mid 1920s Richard Mahrholdt published a catalogue in the name of Waffen Manufaktur Richard Mahrholdt. And Mahrholdt held a stake in Peterlongo from circa 1900 until the late 1930s when the name was changed to Richard Mahrholdt & Sohn. But the connection really dates back further in that Stutzen, target arms, etc. made in Suhl usually had either the Tirolerschaft(Tyrolese stock) or Wienerschaft(Viennese stock). So there appears to be some influence in both directions. But Peterlongo’s early longarms were very distinctive in that the hammer was often reversed on the lock and a snail was constructed/attached to prevent the hot residue from getting in the eye of the shooter. Regarding hammerguns, some sources give that an Austrian poachers gun had an odd underside hammer which prevented the ignition spark from being seen as well as ornate decoration on the longarms. The poachers could have been of the farming class, who were subject to arms restrictions, which were difficult to enforce in remote regions of Austria. Getting off on a longer tangent, the Austrians/Germans were an interesting lot in that in the 16th century citizens were required by law to attend a shooting function 4 times a year in Lindau for example(
http://en.wikipedia.org/wiki/Lindau ) or pay a fine . This was an attempt not to build a militia but to have citizens who could shoot in the event of a crisis. In September of 1912, a law was enforced/passed by the k.k/k.u.k.(
http://en.wikipedia.org/wiki/K.u.k. ) which forced all “antiquated weapons” to be turned in and were to be inspected by curators/officials, by whom a catalogue was supposed to have been made. Then the previously confiscated weapons and the currently submitted “antiquated weapons” were to be put in collections or sent on to arsenals(http://en.wikipedia.org/wiki/Arsenal_(Vienna) ) and museums for display. I haven’t seen the definition of “antiquated weapon” just yet. But the upshot of the above verbiage is that Austria has deep roots in gunmaking and your task is to find a similar Austrian side by side from the same time period which will give you something with which to compare. Keep looking as you will find one.
Kind Regards,
Raimey
rse