Trapdoor Rifles

Just acquired an early M1873, serial # 2214 with what appears to be either an arsenal trials butt plate or a excellent home made butt plate.
It is made of what appears to be brass or some type of smoked metal, yellow in appearance.
There is a rubber shock absorber that extends out of the center of the plate and also behind between the wood. The rubber is now dried and very hard.
The former owner has owned this rifle for the past 35 years and neither he nor myself had ever seen or read anywhere about a butt plate like this.
I was hoping that someone here with many more years of collecting and researching may know something about this plate???
I looked in SRS for any documentation but unfortunately there is none
The rifle is 95% original with excellent blueing. Like another early rifle I have there is no ESA cartouche but has an excellent circle P. The breech block has been updated from the thin firing pin pocket to the thick pocket which is the only part on the rifle that's not original to the serial number.
The bore is pristine, bright and shiny.
Thanks for any help.

I vote homemade from earlier brass musket plate possibly from 1841 Mississippi rifle?

Tom Trevor wrote: ↑Sat Jul 27, 2024 9:48 pm I vote homemade from earlier brass musket plate possibly from 1841 Mississippi rifle?

Most likely Tom, I removed it then tried a plate from another rifle and luckily it fit perfectly so no altering was done to fit the home made plate. I’ll just need to find a correct early plate.

M1841 Mississippi buttplate had the part against the shoulder flat, like the 1816 muskets, so it is not that.

Perhaps from a M1863 Zouave which has a more or less M1855-1888 style buttplate?
It looks like the buttplate has been milled away on the stock side removing about 3/32" thickness so there is a place for the "rim" on the rubber pad to fit between the wood and the buttplate. Pretty clever design, but I have never heard of anything like that before.

John S. wrote: ↑Sat Jul 27, 2024 11:53 pm M1841 Mississippi buttplate had the part against the shoulder flat, like the 1816 muskets, so it is not that.

Perhaps from a M1863 Zouave which has a more or less M1855-1888 style buttplate?
It looks like the buttplate has been milled away on the stock side removing about 3/32" thickness so there is a place for the "rim" on the rubber pad to fit between the wood and the buttplate. Pretty clever design, but I have never heard of anything like that before.

Here are a couple pictures taken with the plate off the rifle.

Zouave sound good and its an early SISSY pad prototype.

I have heard of such butt plates fitted to Remington NY State rolling blocks for match or Creedmoor use. Don't know for sure.