How about aluminum filled bullets for tasks that require long

>>33207491

Wtf op? How am I suppose to eat with science now?

>>33207491
I've been saying this for quite some time, too.

Not to mention, a longer bullet has greater leverage forces which, with proper weight distribution, can be used to induce yawing more efficiently.

>>33207491
Wouldn't fit in the magazine.

>>33207491

But what could possibly chamber a cartridge that stupidly long? Unless it's going to be a proprietary round fired from a proprietary gun.

Don't they already do that with solid copper projectiles? I assume there has to me some kind of minimum density to keep stable.

>>33207491
All the jams from bullets wigging out of the casing.

No, the answer to long range is more weight, better design, more power. Not lightening the bullet and trying to turn it into a dart, how is that shit supposed to feed? That sort of shit will make for fucked up internal ballistics, there's such a thing as too long a bearing surface, also the ONLY bad thing about weight is it needs more power; but who cares about that if your only goal is long range. You can fucking neck down 20mm canon shells if you want to lauch 1,000gr VLDs over the horizon. And chamber them in a singleshot with a barrel life of 100 rounds.

>>33207491
Light boolet + wind =???

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>>33207568

Longer bullets need much more twist. Even sold copper or brass turned projos often go to a gain twist because shoving pencil topedoes into a 1 in 6 twist barrel isn't gentle at all.

With bullets with the same shape and volume, the heavier one with drift less and lose less velocity.

>>33207545
Which magazine?

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>This longer length leads to a better ballistic coefficient

Isn't that (largely) a matter of sectional density, ie the increase in length is (mostly) voided by the reduction in density?

>>33207534
And once it's no longer straight that low density would mean there's very little momentum behind any point in the wound cavity you're trying to create. Shouldn't that make it extremely hard for the bullet to go all too far from straight, and if it does manage that, result in piss poor penetration?

>>33207491

The problem is that spin-stabilization only works well with projectiles having a length-to-width ratio less or equal to 5:1.

>>33207603
>With bullets with the same shape and volume

Which very specifically wasn't the case here.

>>33207563
We're talking concepts here.

>>33207563
Breech loaded guns, break action guns like elephant guns, tanks?

>>33207607
Playboy

>>33207491
>Aluminum has about one fourth of the density of lead, therefore if same caliber is maintained the bullet's would have to be a lot longer to maintain the same weight.
>
>This longer length leads to a better ballistic coefficient, this means that the bullet will maintain more of its speed and therefore will have more power left when it reaches the target, it will take less time to reach the target, and also due to the larger overall speed it will drop less.

Why not go one better and go back to using long spears like the Romans used to fire?

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They already did this in Spain with the 7.92x40mm. I think the case was a lengthened 8mm Kurz. The bullet came in somewhere around 100 grains. I think there are issues with penetration and that's why it was never adopted.

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im just going to leave this here . . .
https://en.wikipedia.org/wiki/6mm_PPC

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>>33207620
Lets say that all these shapes weigh the same, which do you think has the best ballistic coefficient?

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>>33207491
Hello, Dr. Voss.

>>33207741
Issue was they were forced to swallow 7.62x51 NATO caliber NATO redpill.

>>33207620
That may be true about penetration. I don't think it will be difficult to induce yawing. Many long, low drag rounds get by this by having an air pocket in the nose.

For instance, with the formula you posted, what if we have a low-density metal comprising most of the bullet (let's say, tip to the center), then a very dense metal (lead) for the final half? It would be stable in a low-density medium like air, but upon striking a target, your formula will kick in. Given that so much of the projectile is such low density compared to the rear, you could likely assume the first 2/3s to be negligible.

Or, we can utilize the same techniques that low-mass bullets already utilize to increase wounding potential, such as fragmentation.

>>33207992
>first 2/3s to be negligible
I'm sorry, I meant the first half of the projectile could be considered negligible.

>>33207491
The rifling of the barrel is smaller than the bullet its self, in order to propel the bullet effectively the rifling compressed the bullet. Aluminum is less malleable than lead so it would require much greater pressures and continual changing of barrels. It is not a great idea OP.

>>33207939

> weigh the same

BC = SD / i

Any gains you made in i you likely lost in your sectional density.

If those bullets had increasing cross section down your image, then the top item.

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>>33208152
I'm still not quite sure what you are trying to say here.

Ballistic caps are used to make shells more aerodynamic without really affecting the weight of the shell much.

Lengthening the bullet and replacing the lead with a less dense material would have basically the same effect as adding a ballistic cap on a shell.

>>33207589
Reading comprehension: 20%

>>33208344

My bad, I was unaware that that SD for projectiles was not actually computed off the bullets actual volume but rather off of mass / 7000 * (diameter^2), which is kind of weird, but whatever.

So your point stands. Your VVVVVLD bullets should work very well getting to target, with some caveats.

Aluminum bullets would have to roughly 5 times as long as lead to achieve the same mass, so your idea requires us to completely re-chamber every firearm in existence if we want to switch to aluminum bullets.

Also, I really don't think this bullet design is going to hold up well for hunting tough game. A quick google search on Berger VLDs show that several hunters find they perform similar to ballistic tip, penetrating a short distance and fragmenting. An all aluminum version with a ridiculously shallow secant ogive would likely be even worse.

Assuming you don't want to redesign every action in existence, any reason to think you'd do any better than the Berger VLD bullets?

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>>33207491
>This longer length leads to a better ballistic coefficient, this means that the bullet will maintain more of its speed and therefore will have more power left when it reaches the target, it will take less time to reach the target, and also due to the larger overall speed it will drop less.

you are telling me a object with 4 times the wetted area will have LESS drag? fuck you OP.

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>>33208922
Then how do ballistic caps work?

>>33207491
Surely the higher surface area with the same weight would mean it would be affected more by crosswind?

>>33208881
4.2 longer if they were just pure aluminum vs pure lead but you have to account for the jacket which gets lengthened when you lengthen the bullet so id say that 3 to 2 times as long would be more correct.

>>33209034

Logically, the two ideas don't make intuitive sense. Increasing wetted area should increase drag, but apparently does not. I'd like an explanation as to why this is the case.

Also, is there a reason why they didn't make that cone even longer? Is there diminishing returns?

>>33209214

> 4.2 longer

Magnus force is going to stuck fucking with your G1/G7 models at that length.

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>>33209264
I might be wrong but the way i see it the gentler the change of direction for air passing around the object is the less drag the object has.

> 4.2 longer

That would be for pure lead vs aluminum, you have to account for the jacket as well leading to the aluminum bullet probably being around 2 or 3 times longer.

>>33209380

> I might be wrong but the way i see it the gentler the change of direction for air passing around the object is the less drag the object has.
Sure, but why not use that ballistic cap to extend the bullet to 200% of it's length. I wager there is an optimum ogive, and anything past it, the drag from the additional surface area overcomes any gains from ogive shape. I don't have the physics background to objectively know why though.

> around 2 or 3 times longer.
Berger VLDs are already suffering from poor G1/G7 modeling due to the magnus force. 200% longer bullets will be even worse.

While I'm being a negative Nancy, check out http://www.bergerbullets.com/twist-rate-calculator/

.308 (PB) at 2650 m/s, 1.25in long, 168gr, needs at least 1-in-12 twist for stability.
.308 (AL) at 2650 m/s, 2.5in long, 168gr, needs at least 1-in-4.4 twist for stability. That's going to be a shit load of friction.

>>33207621

This post is all you need to read. It's always the same horseshit. Somebody proposes a wildly retarded un workable plan, and someone explains why it's horseshit. But nobody even reads it because it's too much fun to excitedly sperg out about dumb shit with people who are as stupid or stupider than themselves.

TL;DR /thread

>>33209676

Anon, we just overlooked your original post. You don't have to get angry.

It was a very good post though.

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>>33209584
Yeah skin friction is indeed a thing so i guess there is indeed a perfect ratio of length and diameter for nose cone designs.

Would you happen to have any idea btw why bergerbullets mention the secan ogive as the shape for their bullets? Seeing that it's not the most aerodynamic nose cone design out there, seems a bit odd.

And what about bullets in general, i'm not 100% on this but i don't think many modern bullets use the most efficient nose cone designs out there.

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>>33210053

Berger's VLDs already have seating depth issues. Every reloader I've spoken with who uses them runs seating depth / throat jump tests in addition to powder load testing.

Difficulty of construction, terminal ballistics performance, and how absolutely fucking long a Von Karman bullet would be probably have something to do with it.

Look at this thing.

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>>33207491
been there, tried that

>>33207491
>This longer length leads to a better ballistic coefficient
No, it doesn't. It would make the bullet harder to stabilize and drift more in the wind. You want bullets made of denser material, not lighter.

>>33207596
When you need to shoot Hitler from three countries over...

Even as a former aluminum welder I'm not sure (actually not super familiar with the different alloys), but isn't most aluminum brittle as all hell? Also tends to crack a lot.

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>>33210187
I don't know how seating depth is related.

Von Karman nose cone design shape is not too far from a Secan Ogive so i don't really see the construction as a problem if Secan Ogive is a usable shape for a bullet.

Terminal ballistics could be an issue, i do not have much knowledge on the issue.

Von Karman is just the profile, the length and the diameter are not determined by the Von Karman nose cone design. The picture you posted is just the most aerodynamic shape for a given length and diameter.

In this picture LD-Haack or as it is commonly referred to as Von Karman is represented by the C = 0.000

>>33210302
Yes it would lead to a better ballistic coefficient.

>>33210356
For terminal ballistics id imagine it being brittle would be a good thing, another thing of course is how well it would survive being fired. I'm sure that wouldn't end up being the problem though and a functional alloy could be devised.

>>33210358

Long story short, the gentler the taper of a bullets ogive, the more throat jump will affect your POI as the lands of the rifling bite into the bullet. There's not much point in designing a bullet for retaining more energy at 800y if your POI is going to deviate by .5moa (4") each time from throat jump alone, even before the wind starts screwing with your shot.

>>33210372
Perhaps if it had a lead core or only an aluminum tip/jacket. Wind and ANY object the bullet has to go through will fuck up it's trajectory the same way they do with a feather or Styrofoam ball if it's too light.

>>33207491
no, instead use a tungsten flechette arrow with aluminium or polymer sabot. the flechette could be as long as a 223 cartridge almost and it all would still fit in AR and AR mags.

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>>33210986
>flechette

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>>33211020
>bullets are full of spider eggs

Long bullets that are light without sectional density are difficult to stabilize. They would require some serious rifling pitch.

>>33209204
Yes, but not surface area per se. More like the projected area normal to wind direction