Here is another mystery item from the estate that I recently acquired. It is a rolling block of unknown origin. There are no markings on the receiver other than a serial number on the back of the hammer that is visible through the back of the action. I am trying to determine exactly what I have. It is unique in that it has a release lever on the right side of the rolling block. The block is locked in battery until the release lever is pulled back, which then releases the block to rotate back and expose the chamber. There were several Whitney actions included in the parts that I purchased. I am wondering if this might be of Whitney manufacture as well. Has anyone seen another one of these? It has screw in pivot pins rather than captive pins with a side plate. It has holes for set screws to prevent the pivot screws from backing out, but the set screws were missing. It is in good shape with case colors still visible. Any help identifying this mystery action will be appreciated.
Thanks,
Dave

The sling swivel would lead me to believe it's military, and it looks somewhat like some Swede rollers I've seen. I've seen the block type many years ago, but can't remember what the gun was now.

I had another thought, maybe a belgian copy of a whitney. the mainspring mount, the short barrel shank and the slight belly to the reciever remind me of some belgian work. 

Does this look similar ???
I pulled the image from a page relating to the military trials of 1865.
Unfortunately, I couldn't find any info; just this image.
And if you have a copy of Flayderman's handy,check the chapter for Colt ; they had produced some Laidley rifles before Whitney worked with the design.
See ref #5B-259.5
One thing for sure, that's a rare action in nice condition.
Can't be many around.

Keep one thing in mind, the image I found is an ARTIST"S RENDERING, not a photograph.
I was more interested in the placement of the pivot pins; those appear very similar to me.
Furthermore, if you happen to have a copy of Flaydermans handy, and I'm looking at the 9th edition; page 120, Chapter V-B:COLT . At the top of the page is a description of the Colt LAIDLEY rifle, catalog # 5B-259.5
The PHOTO shown is as close to the action in question as I can see.
Whether this action is a Colt product is beyond my expertise, but I would put money on it being a Laidley patent action.
Just my 2 cents.

Yes, the first model Whitney used the Laidley split breech block AND hammer, which was way more complicated than the Remington Rider design; but was considered  "safer" because the hammer support shoulders supported the breech block when the gun was at full cock. Unlike the Remington, which does not support the breech block until the hammer drops and fires the gun.
When the Rider patents ran out is when Whitney played copy cat and brought out his own version of the Rider design known today as the type two.
It is such a good copy, that certain Remington parts will interchange with it .