A major gun collection has a Burnside carbine possibly submitted for trials circa 1865-67 using an entirely different type of cartridge than I have ever heard of. They only have the gun, not a cartridge, so here is a description of what I think the cartridge might look like.
The most unusual feature is that the firing pin strikes the SIDE of the cartridge about 1/16" or less from the base. The firing pin is very small diameter, about 1/16" or less and fully extended only protrudes about 1/16" or less.
The case is possibly somewhat similar to a Crispin or the externally primed Burnside with a belt or swollen area near the mouth. The very slightly tapered rear portion behind he belt terminates in a flat base about .40" -.45" diameter. The mouth end of the case has a belted or rimmed portion shaped similar to a Crispin maybe 1/16" thick and protruding about 1/16" from the rest of the case, but not the very large rounded band around the case like a typical CW Burnside externally primed cartridge. There may be a small bit of the case forward of the belted portion for holding a bullet about .52 caliber. There is an extractor which engages on the rim or belt. It is a dropping block design and the photo is looking into the front of the breech block with it open, Firing pin is at 7:00 o’clock in the bottom of the chamber and extractor is visible at 3 o"clock.
Has anyone ever seen a cartridge designed for ignition by a firing pin strike from the side. Not on a small tit/teat or a cup with a concave base. Or information on a patent for something like that?
Ed Hull’s Burnside book has a photo of the gun, but he knows nothing about the ammo or inventor involved. The gun is marked Burnside’s Patent, Model 1865, Ilion, NY, possibly suggesting that Remington or one of the guy designers associated with Remington are behind this.
Any help would be appreciated.