found an older thread in the double gun forum http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=328096&page=1

Rudolph Berger in Cöthen , today Köthen, got a prussian patent for a new safety on needle fire guns in january 1859

patent for Coburg&Gotha in 1860

Rudoph Berger, court gunmaker for the Duke of Anhalt and the King of Prussia
needle fire double gun cost 95 Thaler

till now I dids not find an early Berger needle fire gun and its not clear what for a type of cartridge was used. proably the old Dreyse paper cartridge with the primer in front of the powder load because the original action allow much longer needles than neccessary for the later paper cartridge and center fire cartridge too. for obturation there must have been a short tube siting on the breech face to slip into the barrel.
Zimmer in his book "the hunting firearms" have a drawing showing a Teschner needle fire gun using the Berger cartridge.

this Speckhahn needle fire double gun with a different action showing this principle:

http://milpas.cc/rifles/ZFiles/Odd%20Fel...%20shotgun..htm

the problem with Zimmers book is that there was a first edition in 1869 and a second in 1876. like todays gunwriter its obvious that Zimmer is writing also about things he had not seen in real life. when making the second edition things of the first and second edition were mixed wild into each other so there are mistakes like in CoTW!

the only version of the Berger gun he is showing is the 1869 up date version that was made maybe first time in 1867/68. it have the 1866 french Chassepot rifle method of obturation of the bolt by a segmented rubber ring which expanded under gas pressure and thus sealed the breech when the shot was fired.

the drawing shows the Berger shotgun paper cartridge with the primer glued on a carton cross in the base of the cartridge. as I say before the hole action of berger needle fire gun shows it was made for long needles reaching a primer between powder load and wad but there were allways problems with cartridges and needles to short so having the primer in the base would help.

Zimmer mention ( in 1876) that Berger was using also the Teschner center fire shotgun cartridge and Teschner using the Berger needle fire cartridge with rubber obturation for his gun when build as a needle fire action but this are things I can not prove now.
Zimmer also mention the "new" modification of the original Berger gun called "Fürst Pless Gewehr" prince Pless gun so it was known under this name in 1876.

Berger in Cöthen - System Patent Berger double gun, imho made in the 1860s

notice the hooks for case extration, maybe for the Teschner shotgun cartridge but in any case not a needle fire gun

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=328096&page=1

this must be a little bit later, again Berger in Coethen, System Patent Berger 16 ga ( or Teschner No. 4?) SN 1604

https://www.liveauctioneers.com/item/11955570_dreyse-cartridge-collath-style-shotgun-by-berger
"An interesting and unusual German side by side 16 bore shotgun. Gun employs Dreyse style needle firing mechanism, and Rudolph Berger Patent action, which was to lead to the Teschner-Collath rotary underlever-opening action, in which a lever under the fore end is connected to a bolt that forces the barrel back against the standing breech, and pulls the barrel down to the action flat. Action, underlever, and tang feature a decorative scroll engraving. 28 inch twin barrels feature Damascus patterning under blued finish, and stock is of burled pattern hard wood, with pronounced cheek rest. Marked on action "SYSTEM BERGER PATENT," and "BERGER IN COETHEN" near breech, with serial number 1604. Bores are very good for the age, and blued surfaces are about 80%, with some thinning to a plum patina, and a hint of surface rust towards muzzle. Stock shows bruising and surface dings characteristic to years of handling, but is free of structural damage, and boasts a dark wood patina. Overall fine example. Caliber: 16 Bore Serial #: 1604"

this gun with the common center fire shotgun extractor

so this how th original Berger gun was looking but between 1870 and 1876 it was transformed into the Fürst Pless Gewehr and production must be going from Coethen/Köthen to a A. Berger in Magdeburg.

this Rudolph Berger /Coethen looks allready like the later guns

http://jagdwaffen.blogspot.de/2013/01/zundnadel-doppelflinte-system-berger.html

notice that the following guns have a different needle/firing pin bolt design that differs older from newer guns. no doubt added for cock and uncock by hand it was maybe inspired by the Mauser 71 firing pin nut.

old model

Fürst Pless Gewehr

Mauser 71 bolt

another center fire double gun showing the long way of the original needle action but now with firing pins
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=316793&page=2
with Ludwig Kloti/Leer on the rib, imho typical Berger quality

Müller in Gotha double gun, underlever in front of the trigger guard

a very late Drilling with top lever to select or cock for the rifle barrel?
R. Haetge/Berlin 16ga x16ga x 11,2x51R Kropatschek-Heissig (or 11,2x52R Schützen cartridge)
http://www.gunworkshop.co.uk/gunworkshop/for%20sale-rifle.htm