Lets say we have two cartridges, they share the same bullet and

>>33466060
The sabot barrel has significantly more volume for the propellant gasses to fill as the projectile moves toward the muzzle. Assuming that the barrel length is the same, and complete powder burn in both, then the sabot round will have less velocity on exit than the necked round. Lower pressure as well.

>What is with these threads lately?

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>>33466095
What about with both barrels having the same volume?

>>33466123

powder has burn time, the powder would still be burning as the sabot exits the barrel, so less burned powder equals less force and less velocity

>>33466139
So lets say we use a fast burning powder and a sabot, could we achieve rifle length performance from a short barrel?

>>33466157
>So lets say we use a fast burning powder and a sabot, could we achieve rifle length performance from a short barrel?

with magic powder maybe

however the max burn rate of gunpowder is about 6000ft/s and the average rifle is about 3000ft/s small necked cartridges out of pistols do about 2000ft/s, you are better off going the 5.7 route in a short barrel than using a sabot, why do you want to use a sabot

I have never heard of anyone using a sabot on a short barrel to get to 3000ft/s

>>33466157
The gas seal wont be as good with a sabot either. With a traditional copper jacketed bullet, the jacket is deformed by the extremely high pressure and fills the entire lumen of the barrel, including sinking into the rifling, creating a much tighter seal, which creates more pressure.

Why would you even want to make a sabot bullet when bottle neck rounds work totally fine?

I tried thinking up some real cartridges you could check out. There are .30-cal "accelerator" rounds which are just sabots. There were some in .308 and .30-06. Try comparing an accelerator .308 or .30-06 to a necked-down wildcat.

>>33466164
>twice the burn rate of average rifle gunpowder
Would this mean half the barrel length then? If the same performance could be achieved with half the barrel length that would be pretty cool, no?

>>33466177
I'm fairly sure that plastic sabots for example gas seal and deform just fine.

>>33466060

okay... what's your end game here?

are you trying to invent something, or are you a writer trying to get some shit straight?

I don't have time to debate details if you're just some autist that thinks he's discovered something 500 years of gunsmiths and engineers hasn't, so out with it.

>>33466206
Just wondering y'know.

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Okay so lets say that we use different sorts of powder so that in both cases all the powder will be burnt (not realistic i know) when the bullet leaves the muzzle, would both bullets have the same velocity at the muzzle?

Wouldn't it be pretty cool to get full size rifle performance from a very short barreled gun?

>>33466238
>Okay so lets say that we use different sorts of powder so that in both cases all the powder will be burnt (not realistic i know) when the bullet leaves the muzzle, would both bullets have the same velocity at the muzzle?

if you could get a good seal with the sabot, maybe

Rifle performance from a short barreled gun is achieved by necking the thing down and using a light bullet, you are not going to be able to accelerate a full size .308 to normal velocity out of a pistol length barrel

this is how you do it:

https://en.wikipedia.org/wiki/FN_Five-seven

>>33466206
>>33466212
Not OP but the reasoning is clear enough to me.

So you can load steel penetrators to shoot elves with without having to cast around it duh. Everyone knows you can't shoot the Fae with lead, it has to be iron or an alloy of iron. How else are you supposed to protect yourself from the pointy eared bastards?

>>33466266
>pistol length barrel
Not pistol length no but since >>33466164
mentioned that there are gunpowders that burn at twice the rate of rifle gunpowder i figured that having half the barrel length while maintaining volume would produce the same muzzle velocity.

Also, 5.7×28mm is pretty anemic i'd say
>only 540 J

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>>33466299
fuck them

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>>33466238
Now what if we did this

>>33466331
top would be slow

straight wall casings are always slow comparatively to necked

>>33466337
oh and it would have way less case capacity meaning less powder

>>33466331
We would have a slow moving and high recoil round that would not have a very big effective range because its trajectory is shaped like a rainbow.

>>33466315
All elves are a trap. Even if they don't have the parts to be a trap, they're still a trap. They'll enslave your mind man. Shoot first, fuck the corpse if that's your thing. As for me I'll stick to developing my anti-elf firepower.

>>33466337
>>33466346
So we created .45

>>33466313
>mentioned that there are gunpowders that burn at twice the rate of rifle gunpowder

I didn't say that, I said the maximum burn rate is 6000ft/s and using that speed gunpowder most rifle cartridges move at about 3000ft/s

some up to 4000+ for small and lightweight calibers with lots of gun powder behind them, you can't make a bullet go 6000ft/s if that is the max burn rate of un resisted gunpowder

>>33466331

ask yourself if shotgun slugs fired out of a short barrel are known for being fast

>>33466238
Seems like you would get a very high pressure spike with the pistol powder/short barrelled version because you are trying to do the same amount of work (accelerate projectile with x mass to y velocity) in a shorter amount of time. The shorter barrel would need to be stronger to avoid kabooms.

>>33466581
True, the short barrels would probably end up heavier than the long barrel would have.

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>>33466299
SS 109, 855a1, steel shot...

>>33466060
>>33466123
>>33466238
>>33466331
Not reading the whole thread, but if you enlarge the barrel diameter, you would not only get a linear enlargement of the barrel material needed with same material (pi*(r1^2-r2^2) with r1-r2 the wall thickness), but also need to compansate for the ability to withstand pressure at different circumstances. Same reason why a Sodacan has a thinner wall than f.e. a paint bucket. Reason why guns have it this way it is, is simply when you go through with the math or tries you will find somewhat sweetspots you construct everything else around.

>>33466060
>What differences in muzzle velocity and chamber pressure would these two cartridges have?
If propellant mass is the same in both cases then peak pressure will be slightly lower in the sabot case, because the propellant doesn't ignite completely immediately but takes a little time. And during this time the projectile is being pushed a little through the barrel. Because of the larger bore diameter, this leaves more volume compared to the non-sabot case.
As for muzzle velocity: It depends amost entirely on acceleration. And acceleration depends on the area on which the gases push. So the sabot will have a higher muzzle velocity. because it provides a larger area fo the gases to push against.

>>33466299
Or just wants a high velocity steel/tungsten penetrator out of a commonish rifle (may have coneidered this with a ruger #1

Couple of material considerations:

1. Super fast burning powder that will accelerate wear on parts and barrel
2. Strong chamber for that larger initial pressure spike.
3. Do we have a dispisable polymer that will withstand traveling down rifle lands at 3000fps without disintegrating?
4. You will need some way to attach the sabot to the bullet to transmit the torque from the lands.
5. Does a much shorter barrel require an even faster twist to stabalize the bullets?

Gentlemen, as we already own the patent for a High Velocity Sabot for a Spin Stabalized Penetrator, we politely ask that you stop posting immediately and remove this thread, lest we are forced to take legal action.

Thank you,
General Electric

>>33467856
Either 1 master troll or 2 seriously guy do you think anyone has the ability let alone capabilities to produce these for anything other than personal use? Let alone you would hav a devil of a time proving damages when you have no market

>>33466095
At least it's a quality thread instead of another shitty general or bait thread.

>>33466060

I tried to work out the work equations for gas pistons, but I gave up. A quick glance at a reloading manual shows that comparable bullet weights in wider calibers require significantly more powder than there thinner-bore cousins to achieve the same velocity out of 24" barrels.

100gr .243, 42gr IMR4831, 3000fps
100gr .260, 46gr IMR4831, 3000fps

Not sure if that's due to more empty space in the case though.