This is an interesting 1886 rifle with full length magazine and an unusual saddle ring. The buttplate also is shotgun/rifle style, rather than carbine. These were popular with the LT WT smokeless style 1886 rifles.
While not completely original, it is interesting. A novel approach for a "sling swivel"... who may have looped a sling from hole to saddle ring. Interesting indeed. I own a full length rifle with magazine, complete with Lyman 21 receiver sight.
My favorites, usually sought, are the solid frame half-magazine SB 1886 rifles. These balance perfectly with the half-magazine, as the takedown mechanism extra steel may add close to 12 ounces in weight.
Interesting rifle, but adapted for the original owner. Of interest, if it could be obtained at the price the seller paid for the rifle.
Ben Lilly carried one of these full magazine 1886 33 WCF rifles with his hounds from Mexico back into the Arizona and New Mexico mountains. It was effective on both mountain lion and bears in the early 1900s. He killed a large
grizzly with his 86 in 33 WCF below Alpine, AZ. along the Blue about 1912.