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The Daisy V/L was a caseless rifle which used the heated air that compressed through a small hole to ignite the propellant and launch the projectile.

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In a world I'm making, I'm thinking that a similar system becomes popular. Black powder is in use that has a nitrated paper to hold the powder and bullet that ignites with the powder during firing.

What I'm wonder is if it's possible for such a system to be used in a revolver system. The biggest issue I see is the gap between the opening for the hot air and the base of the cylinder.

The technological level is that of the middle 19th century, since we are considering revolvers here. Though I imagine that the system itself would be much older.

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  • $\begingroup$ the daisy uses hot gases to expel and ignite the explosive(propellant) contains inside the bullet(cartridge), so now you need to design a sys that produce and inject this hot gases into the appropriate chambers containing many explosives... in short you need to seal the heated gas in a very tight spaces and for a very short timing! $\endgroup$
    – user6760
    Feb 26 at 6:57
  • $\begingroup$ Do you really mean middle 18th century, ie 1750 or thereabouts? Revolvers became a thing more in the middle of the 19th century, and the ability to machine items to anywhere near the necessary precision and to have enough knowledge of fluid mechanics to even devise the ignition mechanism are definitely implausible for the 18th century. $\endgroup$ Feb 26 at 7:40
  • $\begingroup$ Oops! My mistake, I meant 19th century. I’ll fix it up. $\endgroup$
    – Seraphim
    Feb 26 at 7:45

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The V/L system was pretty much an air rifle designed to employ dieseling. Even in the absence of the caseless propellant, the gun would still propel a bullet downrange on air pressure alone.

The problem with a revolver is that a large compression cylinder is required to compress air sufficiently to ignite the caseless propellant. A carbon dioxide cylinder as used in modern air pistols would not work, as the temperature of the carbon dioxide would fall as it exited its cylinder.

It might be possible to mount the compression cylinder in the handle of a pistol, but then delivery of the air to the revolver cylinder would be troublesome, with losses between the revolver frame and cylinder being inevitable. However, this may not matter as long as the hot compressed air can ignite the propellant, since the ball valve will close as soon as the propellant ignites, making the volume of air delivered less relevant.

However, the Daisy V/L was known for its inaccuracy due to variable muzzle velocity. The exposed caseless propellant was hygroscopic and prone to crumbling after a time, and the high air pressure required to ignite the propellant would require that the bullet would have already begun its journey down the barrel by the time that the propellant ignited. Additionally, in a revolver, inadequate seal between cylinder and barrel would result in loss of gas pressure that would only increase with wear.

The ball valve would likely mean that there is little possibility that the weapon's gas cylinder could be re-cocked by the pressure of the caseless propellant, so it would be necessary to operate a lever to cock the weapon for another shot, compressing a heavy spring, making such a weapon little different to a bolt-action pistol with a magazine at best. The movement of the piston within the grip would likely cause motion that would reduce accuracy.

Since the V/L system was a curiosity, it is not really known how long the ball valve would last, but locating the ball valves in a cylinder would mean that the cylinder could be easily replaced when it wore out, and entire loaded cylinders could potentially be swapped. This would work with the design of early cap-and-ball revolvers having cylinders with black powder loaded into the chambers and a ball press-fitted into the top.

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  • $\begingroup$ On the topic of the inaccuracy. I was thinking that a combination of a using the paper as a wadding along with a much heavier round (.44 to .45) round ball relative to the air volume that was being compressed as it would only need to ignite the paper/powder. In theory meaning that it would not suffer the inaccuracy of the inspiration. Or at least lower the issue to manageable levels. $\endgroup$
    – Seraphim
    Feb 26 at 7:25
  • $\begingroup$ @Seraphim If you jam the ball in the cylinder chamber hard enough, the air pressure probably won't move it. $\endgroup$
    – Monty Wild
    Feb 26 at 7:45
  • $\begingroup$ It’s not the air pressure that moves it, it’s the ignition of the powder that does. Which itself is ignited by the heated air of the piston. $\endgroup$
    – Seraphim
    Feb 26 at 7:46
  • $\begingroup$ As I said, the V/L effectively uses airgun dieseling to ignite the propellant. The trick is to minimise bullet movement before the propellant ignites. $\endgroup$
    – Monty Wild
    Feb 26 at 7:52
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    $\begingroup$ That's pretty much it, save fore the reliability of the ball valve As long as the air gets hot enough, it'll ignite the paper/powder, and the ball valve should shut, preventing blow-back. $\endgroup$
    – Monty Wild
    Feb 26 at 8:29

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