I don't want to hijack this thread any more than necessary but since it's relatively pertinent, here's an even odder-looking cartridge case used by another popular ACW carbine. It also had a fairly good gas seal system and was used in larger numbers than the Maynard. I just purchased one from a guy who specializes in ACW firearms and acquired a book to learn as much as I could about it.
What I acquired was a very nice 5th model Burnside carbine (circa 1863/4) in good shooting condition. Burnside's design is only like the Maynard in that it has no integral primer--just a small vent hole at the rear, but the gas seal system is totally different. It uses a reverse taper for the body with a large obturating ring at the mouth of the cartridge. A lot of people think a loaded Burnside round looks a little like an ice cream cone.
My cases also came from S & S as did the cast lead .54 cal conical bullets they stock. Even easier than Maynard, the Burnside cartridges can be reloaded on the fly since they really don't even need a hammer to load. Bullet depth is controlled by a turned step inside the cartridge and any waxy bullet lube seems adequate to hold the bullet in place. I also just received a Lee two cavity .562 cal round ball mold from a seller on eBay to use in the future. Unlike the Maynard, the Burnside doesn't resemble anything used after metallic cartridges became commonplace.
In 1865, the Burnside company stopped making their carbine to instead fill a new contract with the US government making the M1865 Spencer. These were used by the US cavalry in the early years of what is now referred to as the "Indian wars" period.
With 55,000 units produced and issued, the Burnside was the 2nd most used breech-loading single-shot carbine after the Sharps. There were only about 22,000 of the Maynards produced but I've not come across any reasons yet why more Burnsides were purchased than the Maynards. The Burnsides did have their hammer mounted on a side lock so the rear sight wasn't crowded and it also came with a wood forearm starting with the 3rd model. Black powder can heat up a barrel pretty fast with continued firing.
The Burnside did not use a round ball historically but according to some of the shooters at N-SSA and the linked video below, the gun is quite accurate with this particular round ball. To cast the conicals one has to order a very expensive custom mold plus handles. At $5.50 per cartridge, the brass also isn't exactly cheap but then they will supposedly last for a lot of reloads. I'll probably hand anneal the mouth ends after a few shots to make sure they last longer.
Here's what the loaded cases looked like using the conical bullets from S&S with 2 lube grooves. The wooden block came out of a repro leather carbine cartridge case identical to the one used in the previous video. I used 40 grains of 2 FFg Goex which left room for a .45 cal Oxyoke unlubed felt wad under the lubed projectile. The FFg grain size is large enough that the powder won't leak out of the vent hole.
View attachment 1113125
Below is a Youtube video that the "Cap and Ball" guy from Hungary did on shooting the Burnside using the round ball. There were no cases available in Europe, so while he was waiting on a shipment from the US, he used his own lathe to turn a few. I will eventually cast some of the round balls with my Lee mold to try also.
Cap & Ball's video
As mentioned, I don't want to hijack the thread any further but if
Denton says it's OK, I will post some pictures of my new (158 year old ) carbine.
Cheers