Rimmed, Bottle Neck, Two- Piece Rifle Cartridge Case

I have run into a brick wall in attempting to identify these cartridge cases.
I took the time to measure and draw the cartridge case specifications. In all, the specs run +/- 0.002". Along with the drawing, I have taken a few photos showing side and base head views. The side views have a caliper included which is opened to 2.000" (two inches).
The cartridge case consists of two pieces, the body and the base section. You will see that the cartridge is that of a bottle neck rifle cartridge.The cartridge body(one shown in photos) is brass composition. The base is composed of iron and has been color cased hardened. The color case hardening is difficult to see in the photos. The rim is knurled.
I did check the base and the body with a magnet to confirm the physical appearance. The base is magnetic and the body is non-magnetic.
The side view photos, which includes a case body only, shows the bottom of the case having a centered thru hole. This hole is smooth and un-threaded with a diameter of 0.225". A visual inspection inside an assembled cartridge case reveals a slotted, semi-dome fixture with a centered single flash hole. The flash hole is 0.038" in diameter. The slotted semi-dome fixture has a diameter which appears close to the inside diameter of the case body bottom. I believe the slotted semi-dome fixture threads onto the cartridge case base so as to lock and secure the cartridge case body/base assembly.
I have not attempted to dis-assemble in fear of damaging the cartridge cases. Using a 5X and 10X loop, I could not find any inspectors or I.D. markings.
I contacted the IAA for assistance and help in possible identification. I have learned that currently there are no known “Draper”(Wills patent circa 1864) bottle neck rifle cartridge case specimens. With the attachments ( drawing and photos), this written brief, can anyone assist with either more information or a positive identification?

It looks like one of the E. Remington two-piece cases from the 1870s or a bit later. I have only a single specimen of a case body without the knurled steel base so am unable to confirm the similarity of your specimen to a known example. Yours seems close to the .44-77 Sharps and Remington. A better identification should show up before long. Jack

Herschel Logan’s book Cartridges has a good cutaway of this cartridge, along with some of the text from an original box label. One case comprises the brass body, steel head with knurled rim, and a steel screw which enters through the case mouth to thread into the base and serve as a primer anvil. I didn’t copy the label text, but it isn’t very helpful in terms of dating or origin of the design. The example in Logan is a .40-70 Sharps necked. Jack

Jack, thank you for the information and direction. I will review logan’s book. In addition, I’m going to perform an early cartridge patent search for C. Sharp and E. Remington. Understanding that they may not be the inventor(s), I may get an assignee hit on this particular design. Will keep you apprised of findings.