Here is a link to one of the oddest guns I have seen come to auction in a while.

https://www.gunbroker.com/item/957655470

I bid on this early because it is unique and aears nicely made.I am a sucker for something like this. However, the price seems to have gone way past anything in that category after the first week.

There is no provenance, no markings, no caliber. It looks like some sort of Martini has been skeletonized and full stocked, with a custom top lever joined to the breechblock. A .700 bore could be a period attempt at the mythical 70-150 winchester. MY guess? I was bidding with the thought that it is a 12 ga bore rifle. An outside guess is that it was based on a Greener Police shotgun. Bore is about right for the original barrel and it could have been rifled to 12 ga depth. It could also be one of the Lancaster series of cartridges.
You might find the action maker on the sideplates under the stock, but I suspect it was completely cut away to make the stock thick enough.

The most intrigueing thing is that I have looked and looked, even at the Hi Def images, and there doesn't appear to be any kind of barrel/action joint visible. Integral unit????

No maker and no manufacturer, alond with no caliber. That's too many unkowns for a wild bid. There is still 5 days to bid.

It's a money-walker, I assume they are fairly uncommon but I have at least seen them for sale before. it's likely a bore rifle.

Monkey tail

I've also bought an odd falling block within the last couple of months should be on the way from England this week. It's a Giles Whittome made for Purdey's as a test gun. 10 bore falling block paradox.

Money-Walker as suggested above. Forgotten Weapons

Thanks for posting that video. What a cool rifle! If it was a reasonable caliber, I'd be bidding on that one.

Vickers-Armstrong made some Martini rifles in the same way. Barrel and receiver all in one piece.
https://www.highwoodclassicarms.co.uk/Firerms%20For%20Sale/0210.htm

I have one in 577 Snyder and it is a fun rifle to shoot. Mine came out of India and it is not a nice but shoots well enough for it's 150 years.
Cheers,
Laurie

I purchased it as I thought I would sell my 577 Snyder. Well it isn't working out.
This one is a very much larger action and it is a fully rifled 12bore! The bore is excellent.
Cheers
Laurie