Is this a primer?

I found this cartridge in a bucket of ammo. It looks like just a solid piece of brass where the primer should be. My picture didn’t come out the clearest but I hope it shows what I mean. It doesn’t look like the groove around the primer was machined out, but it does look fairly old to me. The bullet is a roundnosed lead with a bit of white oxidation. Is this some sort of weird priming, or just a cartridge that has been fooled with?
The groove around the primer is deeper than it appears in the picture, I am guessing about the thickness of the rim. I couldn’t get anything into the groove that would reach the bottom
Measurements are as follows
OAL 1.455 “
case length .910
rim dia .495
case dia .440
bullet dia .437 (at the widest point outside the case)
rim thickness.052
"Primer” dia .215

Looks like a Martin primed .44 pistol cartridge ( I’d say 44 S&W american)

Here’s a sectioned Martin primer to show you how they were formed.


Thanks, I had never heard of this before. Is this is another version of inside priming? Would this be considered rare or uncommon?

edited to add I googled Martin Primed Cartridge and it brought me to the reference section of this site :)

A very early US inside primed case. The version earlier did not have the extra fold in the head at the corner (shown in Rays photo) where the rim meets with the body, it was just “L” shaped, As to how hard to find - yes, uncommon, but by no means rare or even scarce. Developed in the early 1870’s & mostly (all?) made by the US government arsenals for the military.

Somewhat short lived and predates the Benet primed case system.