Thanks! I did have a poster on RFC note that it was a "Model 87" Winder Musket receiver, and that the four holes on the side of the receiver are for the Lyman #53 receiver sight, which is specific to this variant. These apparently came both US-marked, and commercial, but I didn't note any US markings on this one.

Here's a nice article from the November 1956 American Rifleman that reviews the history of the Winder Musket and its variants:
https://archive.org/details/sim_american-rifleman_1956-11_104_11/page/34/mode/2up

The above article also refers to the 3rd Model as a "Model 1887".

It was also commented that using the Model 87 was not an obvious choice as the basis for a custom rifle, if you weren't going to be using the Lyman receiver sight. The other three Dubiel 1885's I linked don't appear to be Model 87.

Here's another example of a Model 87, with the Lyman receiver sight:
https://www.gunauction.com/buy/1147...-short-winder-musket-model-87-c-and-r-ok

I've also noted that it is a bit unfortunate that Pope installed the Weaver 440, as the top of the barrel is D&T'd for an externally adjustable scope. It didn't look like one had been installed, and I suppose the Weaver 440 scope (introduced in 1933) was the new cool thing at the time.

Last edited by btbell; 08/17/21 02:10 PM.