Horst Auctions in Ephrata, PA, is holding a big gun auction on Saturday, 11/6.

Here is a listing plus pics of everything in the auction. There are plenty of good guns there. Lots featuring double barrel shotguns are listed below:
108. W. W. Greener hammer double ser.# 23915.
110. Parker Bros. “T” Quality ser.# 76804.
112. Baker Gun Co. “Model 1897” ser.# 32066.
114. Moore & Harris percussion double ser.# 500
116. J. P. Sauer & Son hammer double ser.# 239414.
118. Browning “Citori Lightning” ser.# 27339NX773
123. Parker Bros. “VH Grade” ser.# 179744
135. Ithaca “Crass Quality 1” ser.# 92137.
137. Parker Bros. “Lifter Action” ser.# 8399
141. Moore & Harris percussion double ser.# 4227
145. Remington Arms Co. mod. 1889 ser.# 252033.
147. A. H. Fox “Sterlingworth” ser.# 91323
149. J. P. Sauer & Son mod. V or 60?? ser.# 141721
180. A. H. Fox “Sterlingworth” ser.# 122724
185. Savage-Fox “Sterlingworth” ser.# 266415
202. Parker Bros. “G” Quality ser.# 64751.
203. Browning “Superposed” ser.# 2785.
204. J. P. Sauer & Son mod. V or 60?? ser.# 122997
205. Lefever Arms Co. “H Grade” ser.# 58831
207. Charles Daly “Superior” grade ser.# 1771
209. Meriden Firearms Co. “The A. J. Aubrey “T” Quality” ser.# 2949
210. Remington Arms Co. mod. 1900 “Trap Gun F Grade” ser.# P135125
212. A. H. Fox “CE Grade” ser.# 31688
213. Lefever Arms Co. “G Grade” ser.# 47604.
214. G. L. Rasch hammerless ser.# 672
215. G. Hemenway hammer double ser.# 6321
216. Prize Machine Gun mod. 1883 ser.# 28946
218. Parker Bros. “G” Quality ser.# 129283
219. Darne mod. R10??? ser.# SPC623. — 20g
259. Regina hammerless ser.# 1421
260. A. H. Fox “A Grade” ser.# 301319. — 16g
262. Parker Bros. “G” Quality ser.# 89164
263. W. & C. Scott & Son “The Monte Carlo B” ser.# 70886
264. W. & C. Scott & Son “The Excellentia” ser.# 34334.
265. George Gibbs mod. unknown ser.# C700.
266. Lefever Arms Co. “BE Grade” ser.# 39303
267. H. Clarke hammer double ser.# 8516.
268. Charles Holloway hammer double ser.# 1213