How strong are cartridges?

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Derringeer

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When a brass cartridge is ignited, it expands into the walls of the chamber. If a cartridge would be ignited outside of the chamber, it would blow up. In a chamber where the cartridge isn’t fully supported it cracks.

So my question is, what would happen if you made a oval chamber that could take multiple rounds stacked together on top of eachother? Would they still blow up at the weakest spots which are in-between them, or would the geometry make them hold up better?

Here’s a picture that describes what I mean, seen from behind
2nPrhM8.jpg
(each number represent a round, in this case it’s 3 rounds, so the yellow area are rounds/brass and the grey are is the steel chamber)
 
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tipoc

New member
Well when a primer is detonated it ignites the powder to burn. That burn is very rapid but not an explosion. The pressure from that burning powder pushes outward in all directions at the same time and rate. This causes the brass to expand. The expansion is stopped by the walls of the chamber, and the rear of the breech, which directs all the pressure forward against the base of the bullet and so "bang".

After the expansion of the brass some retraction also occurs. This is what allows for simple extraction.

When a bullet is ignited outside a chamber and not limited by any surrounding walls the case expands rapidly to it's limits and may crack at it's weakest point. This diverts alot of the pressure away from the base of the bullet. The bullet will essentially drop from the case with little forward energy. The base of the case has nothing behind it. So the case is almost as much blown away from the bullet as the bullet is thrown out of the case. Possibly more depending on the weight of the bullet.

So in the one on top of the other design you have above. Do all the rounds go off at once, or one at a time?

With no walls between the rounds the cases would expand more into the case below, or above it, tending to stick. The whole operation would be dirty with fouling as well. Extraction could be an issue.

There is a reason no one has built a design like this.

tipoc
 
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Derringeer

New member
Schlitz 45 It’s true, atleast regarding smokeless powder which need pressure to burn fast and generate high pressure. But in my scenario, the pressure is generated inside of the cartridge since there is a barrel infront of it, so the bullet can’t escape. Compare it to a chamber cut in half with a barrel that the bullet is forced into, then the case will explode.

However, in my example the chamber isn’t cut in half like that, so the cartridges are more supported, both by the chamber and the other cartridges. So my question is if the pressure will give enough focus on the small area along the cartridge that the steel chamber isn’t supporting to blow it out, and how much strength will the supporting cartridge beneat give to prevent that?
 
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Derringeer

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Tipoc
The cartridges are ignited one at a time. Here’s another version which require even less support of the chamber
WILhhob.jpg
 
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tipoc

New member
The brass would expand into the open area beneath or above the case. Depending on the pressure of the round that would be more or less pressure.More or less potential expansion of the brass case.

For the top and bottom round the case would expand as normal except for the area below, or above it where there is no steel wall to contain the expansion of the brass. That brass would expand into the brass below it or possibly crack.

For the center round the brass would expand both above and below.

Some velocity would be lost. Some fouling as well. That would be more or less depending on the width of the gap in the cylinder walls between rounds.

Extraction and fouling could be an issue.

Again is the plan for the rounds to fire one at a time or simultaneously? OK I see you said one at a time.

Also, why?

tipoc
 
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Aguila Blanca

Staff
Derringeer said:
When a brass cartridge is ignited, it expands into the walls of the chamber.
Click to expand...
Correct. (Well ... sort of)

If a cartridge would be ignited outside of the chamber, it would blow up.
Click to expand...
Incorrect.

In a chamber where the cartridge isn’t fully supported it cracks.
Click to expand...
Incorrect.


Derrigeer said:
Schlitz 45 It’s true, atleast regarding smokeless powder which need pressure to burn fast and generate high pressure. But in my scenario, the pressure is generated inside of the cartridge since there is a barrel infront of it, so the bullet can’t escape. Compare it to a chamber cut in half with a barrel that the bullet is forced into, then the case will explode.
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In other words, you are on a firearms forum asking a question about something that is a bomb rather than a firearm cartridge.

Does that about sum it up?
 
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tipoc

New member
Wait? I just looked more at the second pic.

There is blessed little support for the rounds. So it's likely the cases of all three would rupture and the bullet leave the barrel at greatly reduced velocity and ridiculously poor accuracy over any distance. You'd also have to clean every chamber thoroughly before another round could be loaded. Extraction could be tough, as well.

Does it have three separate barrels?

Is this still a gun? What would the point be?
 
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Derringeer

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Tipoc & Aguila Blanca
Well, I’m experimenting with something as odd as a ’magazine’ for a superposed muzzleloaded gun.. Actually the cartridges isn’t only cartridges inside of a chamber, in this case they are whole barrels themselves.

I’m seeking for a solution that will allow a design like this. Ordinary thin brass cases wouldn’t give enough strength I guess, but since the ’cartridges’ will support eachother they still don’t need to be as strong as a barrel made of steel that can handle the fire on its own, if that make sense..
 
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Derringeer

New member
Tipoc
I use the same superposed concept as the first pistol does, but I only load two loads in the barrel instead of four (because of overcompression caused by recoil), and instead of a flintlock mechanism I use electric igniters to ignite the gunpowder..

The idea is to make a hybrid of the ”ratchet pistol” and the ”howdah pistol” basically, but instead of a set of preloaded barrels as magazines I thought about making preloaded ’cartridges’/thin barrels that could be inserted into a main barrel, making it more practical..
 
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Aguila Blanca

Staff
Derringeer said:
Well, I’m experimenting with something as odd as a ’magazine’ for a superposed muzzleloaded gun.. Actually the cartridges isn’t only cartridges inside of a chamber, in this case they are whole barrels themselves.

I’m seeking for a solution that will allow a design like this. Ordinary thin brass cases wouldn’t give enough strength I guess, but since the ’cartridges’ will support eachother they still don’t need to be as strong as a barrel made of steel that can handle the fire on its own, if that make sense..
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It makes no sense at all. In a previous post YOU wrote:

But in my scenario, the pressure is generated inside of the cartridge since there is a barrel in front of it, so the bullet can’t escape.
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If the bullet can't escape, you don't have a firearm. The purpose of a firearm is to expel a projectile. If the projectile (the bullet) can't escape, you don't have a firearm ... you have a bomb.

Your explanations are also extremely confusing as to what's a barrel and what's a chamber. Again, with all due respect, nothing you have presented makes any sense to me so I can't be of any help to you.
 
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44 AMP

Staff
I think you are making a fundamental mis-assumption.

A cartridge SEEMS to detonate but what really happens is that it doesn't blow UP so much as blow OUT.

And, the amount of the effect varies with the amount of pressure. In some cases, low pressure rounds simply have the case "pushed" back off the bullet (the case is lighter), and as soon as the separate the pressure is vented, and the sometimes intact case comes to rest a short distance from the bullet which may not have moved, at all.

At higher pressure levels, the brass reaches its strength limit before getting free of the bullet and ruptures (cracks / splits) sometimes at more than one point. And, at centefire rifle pressures the case can fragment SIMILAR to a grenade in appearance, but in a random manner.

When a case is partially supported the unsupported area is what usually lets go.

In your first drawing, with the rounds in contact with each other along a narrow area, it is very likely that the first round to fire will split where it is only "supported" by the other case. The other brass cases are no where near as strong as steel. So, the first round splits and high pressure gas "vents" against the unsupported body of the next case, possibly crushing, deforming it, possibly detonating that powder charge and creating a cascade effect of all rounds detonating sympathetically.

Something like this is what "killed" a lot of tanks in WWII. A hit in an ammo storage rack setting off the powder of one or more rounds and that setting off multiple others, with the resulting large explosion "killing" the tank and often the crew.

I think with anything above the very lowest pressure levels your multiple "partial chamber" gun would detonate all powder in it in an uncontrolled manner. Dangerous, almost certainly.
 
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big al hunter

New member
Since you are planning this as a muzzleloader, you need to study cap and ball revolvers. If loaded improperly, a cap and ball revolver can ignite adjacent cylinders simultaneously when the chamber aligned with the barrel fires. It's not good for the gun, or the shooter.

When loading from the muzzle you have no way of positively sealing the separate charges from each other. It will chain fire from one charge to the next. The pressure involved forces burning gas between the steel / brass and the bullet in the adjacent positions in the "magazine", thus igniting the powder charge.

Because you have removed the complete circle of steel around the chamber, it leaves a weak spot in the steel. The magazine area will likely expand to the point of failure as all of the charges ignite nearly simultaneously.

Think about the warnings you have received here before you pull the trigger on this one.
 
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Don P

New member
Absolutely FALSE. I have 7 stitches in my arm, from a cartridge going off in my reloading press trying to seat a high primer. A piece of the case a little smaller than a dime was remover from my arm along with a $2,000 ER bill

You can find the post in the reloading section with regards to seating high primers post #3 dated 7/15/17
 
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Mal H

Staff
Don P, please clarify what you are saying is absolutely false. Without that clarification, it appears you are saying that what big al hunter said is false, and I doubt that's what you meant.
 
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Don P

New member
I was referring to post number 2. I tried to post the links to my photos and post from the reloading thread without success. I am making no reference to a muzzleloader. Mal if you could link up the photos for me from the thread I would Appreciate it.


[Edit by Mal H]
Here is the post with the images of the injury:
https://thefiringline.com/forums/showthread.php?p=6491089#post6491089

The first image looks like a thumbnail image, and not the regular sized one.
 
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reddog81

New member
Too many variable to give any useable answer. Different cartridges have different brass thickness, various pressure levels, varying bullet weights, etc. Pressure will always seek out the path of least resistance.

If you use thick enough brass and low enough pressure it'd be easy to create something that pushes the bullet out the barrel without igniting the 2nd cartridge.

Are you making the cases yourself?
 
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Aguila Blanca

Staff
I still don't understand the point of making a firearm that doesn't allow a bullet to leave the barrel.

Derringeer said:
But in my scenario, the pressure is generated inside of the cartridge since there is a barrel infront of it, so the bullet can’t escape.
Click to expand...
 
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