We all know what a typical chamber pressure plots look like, pic related.We also know that the bullet energy is basically the area under the plot.Now, why don't we make a combination powder with fast + slow powder so instead of a triangular shape the pressure curve looks more like a rectangle? This way we can maintain high chamber pressures all the way until the muzzle. We could achieve significant area under the curve increases with this, as much as +50% compared to traditional powders that have very little pressure left over by the time the bullet gets to the muzzle.
>>64738767>Now, why don't we make a combination powder with fast + slow powder>What is modern double base propellantsAnon you understand that triple and polybase propellants are actually experimented on, right?
>>64738767>make a combination powder with fast + slow powderBack in the day before we had the selection of powders we have today people did exactly that. go read up on the original .454 Casull load, it was a layering of 3 different powders in the case.Nowadays we engineer powders to have different burn profiles. It's more complicated than just "fast" vs "slow". Look closely at smokeless "powder" and it's not really powder at all, it's tiny little flakes, spheres, donuts, sticks, lobed sticks, hollow tubes, or other funny little shapes. It also has coatings on it. All of that is done to give it the right combination of "fast" and "slow" for a given purpose.
>>64738767https://en.citizendium.org/wiki/Gunpowder
>>64738767We already try to do that. We're trying our best okay? This is the best we can do with current technology. We all know a horizontal line is the holy grail, but it's just not possible right now.
>>64738890Look, all I want is an actual good reason to use 20'' barrels, please make it happen.
>>64739110You have them already. Double base powders are dead common, triple base powders are less common but still available, and some boutique ammunition manufacturers use duplex powder charges.
>>64738767Part of it is that the amount of energy you can get is based on the amount of powder you can fit into the cartridge. I don't think you can flatten out the curve without reducing the peak height unless you start using more energetically dense materials than nitrocellulose. The other issue is that as the bullet moves down the bore, the available volume increases, and it becomes increasingly difficult to create high pressures.I think tricks you can play like double/triple based powders or mixing powders can only stretch the curve a bit. I think if you really wanted to push things further, you'd probably need a fundamentally different propellant and a fundamentally different way to modify its decomposition.
>>64738767im pretty sure a pressure chart will always look like this simply because of physics the pressure spike isnt from the rate of powder burning, but due to it being confined in the sealed cartridge. as the bullet flies down the barrel the pressure gets lower because the combustion volume increasesif you want the same pressure the entire time the bullet is in the barrel, youd need way more propellant and it would somehow have to burn at a linear rate. something like a potato gun but its a cartridge
>>64740306RDX and other high energy propellants are already a thing, just not for civvies. Some real black magic goes into stupidly high performance autocannon rounds like the 25mm Bushmaster sabots.>Barrel burner>Do all sorts of flame temperature lowering and protective coating for barrel>Barrel life goes way the fuck back up
>>64740448HMX might work too. I imagine the carveouts for smokeless powder in the law is the main reason they haven't gotten too creative with the powder composition. That, or the cost (r&d and feedstock costs) are too big of a disincentive.
