Mile-Per-Second Cartridge: Is it possible?

[John Wayne]

Ok, there are a number of production and wildcat cartridges now that top 4,000 fps. The .243 can do it, as can the .300 Weatherby Mag, if not in factory loadings. This is a velocity a lot of people thought would never be possible.

Is it possible to create a cartridge that fires a projectile at 5,280 fps? What kind of velocity/ballistic coefficient would it take to actually make a projectile that could travel 1 mile in 1 second?

Before you post:

-Yes, I know barrel life would be terrible, muzzle blast, flash, cost, etc. This is pure speculation about whether it can be done using current materials available.

-I also know there is no point. Nothing magic about bullets at 5,280 fps other than the fact that it coincides with a number we associate with the number of feet in a mile.

-For the purposes of this question, I am talking about a projectile with a muzzle velocity of 5,280 + fps, which still won't travel a mile in one second. If you want to run the numbers on how fast something would have to be going at the muzzle in order to actually cover a mile in one second, feel free to post it.

*EDITED TO ADD: Within the confines of something that could be classified as a shoulder-fired rifle (or smoothbore), using a conventional primer, percussion ignition, brass case, and non-saboted projectile.

 

[dmancornell]

Paris gun.

 

[John Wayne]

Sorry, didn't mean to include artillery. I was wondering if it could be done in something that would qualify as small arms, not artillery.

Oh, and according to Wikipedia, the Paris gun only hit 5,250 fps

 

[2ndAmFan]

If I remember correctly, the late Frank Barnes developed a .22 caliber round that had a muzzle velocity of 6,000 fps while he was doing research for the US government. As you mentioned, muzzle wear was very bad and I think the rifle was trashed after some 5 or 6 rounds. I don't remember the specifics, and I am not sure if the ballistic coefficient of the bullet was even published. No telling how close this projectile would come to covering a mile in one second without more info, which I am afraid I don't have at hand. Maybe another member knows more about it than I do.

 

[Rembrandt]

Not sure why the exclusion of saboted projectiles.....one would think sabots would reduce barrel wear and prolong barrel life at higher velocities.

 

[2ndAmFan]

The muzzle wear problem isn't the speed of the projectile so much as the heat of the burning powder. It burns and melts the barrel of the rifle. If there was a way to use the propellants utilized by big guns, which burn at a lower temperature, at least that problem would be solved. So far as I know, no one has yet developed a way to do that. People are working on all kinds of ideas though.

 

[jerkface11]

This is close enough. http://www.reloadersnest.com/detail.asp?CaliberID=100&LoadID=1147

 

[Naybor]

That is a good question to think about.

Some problems would be "Can the bullet withstand the air velocity at those speeds?" Will the barrel give a reasonable life?

Most modern bullets will self destruct when traveling at more than 4000 fps. by hitting only one blade of grass, one flying bug, or one raindrop. Hitting a prairie dog at that speed will produce spectacular results and what is referred as "red mist" by vaporized blood. Also accuracy is adversely affected by speeds greater than about 4000 - 4500 fps.

For a while, scientists were experimenting with magnetic rail guns that would accelerate a projectile to incredible velocities. One of the problems was the rail gun was destroyed with only one shot.

5280 fps at the muzzle may be attainable, but probably won't be practical.

Again, good question.

 

[Sebastian the Ibis]

There is a guy on this board, I think, that tried to neck down a .50 bmg for maximum velocity for some engineering school project. I can't remember how fast he got it going, but I do remember his smaller bullets would spin apart when they left the barrel.

 

[kayak-man]

IMO, and this is mostly conjecture, I think that the way to go about it would be to have a small, but long projectile, and a really, really big case.

The platform: A bolt action 50BMG rifle, like this http://www.serbu.com/top/bfg50.php

Bullet: A 50BMG round, necked down to take a .22, .25, or .30 caliber bullet. I'm thinking the projectile would be a little longer than usually, with foster slug style grooves cut in it to improve stability. Perhaps mix a wee bit of oxidizer into the propellant, just because, ya know, we already necked a 50BMG down to a .22, so why not?

End Result: A very big boom, lots of muzzle flash, recoil might actually be pretty decent because youre not shooting that large of a projectile. Something is going to break, either the gun, the brass, the target, the backstop, your collarbone, or some combination of the above.

Unintended result: Some where in North Korea will be a map with a circle around your house. The circle will be labeled "Abandon all hope, ye who enter here."

Honestly, If I could afford it and had the materials/tools, I'd be out back trying to build one of these right now

Chris "the Kayak-Man" Johnson

 

[Jubjub]

It would be pretty tough to get a conventional bullet to that speed, but a smoothbore with a flechette riding in a sabot has been pretty close. The Steyr ACR had something like 4,700 fps muzzle velocity, and the technology is certainly not fully developed. Tank guns using the same concept are pushing 6,000 fps.

The Steyr round used a plastic case, but the sabot and flechette are the same as these rounds.

 

[2ndAmFan]

A lot of bullets will self-destruct just at high velocities without hitting anything but air. Many bullets traveling at 4,500-5,000 fps will be spinning at such high RPMs they will literally unravel. A jacketed bullet is pretty much out of the question as it will never hit the target. It will be in pieces before it gets very far from the barrel. Likewise a hollow point or X bullet. A solid slug which can withstand the extreme RPMs would at least survive to hit the target.
I read about experimental smoothbores Jubjub mentioned shooting flechettes, more like small crossbow quarrels really, that were achieving very high velocities, but I can't say any of them were capable of covering a mile in one second.

 

[kayak-man]

Jubjub, those are some pretty neat loads!

Chris "the Kayak-Man" Johnson

 

[Acera]

The spin rate of the bullet can be controlled by the rifling twist rate. If it is going too fast, lessen the twist.

I can see the issues with trying to achieve high speeds with conventional twist rates. If you are going to spend the dollars and effort to develop a high speed round, spend the money on getting a slower twist barrel also, eliminating all those concerns about the bullet spinning itself apart.

 

[Owen Sparks]

Even if you could get past 5280 fps at the muzzel the bullet would not travel one mile in a second. Air resistiance would slow it way down over such a long distiance.

 

[Freedom_fighter_in_IL]

Just guesstimating here but I would think you would have to achieve a Muzzle Velocity of close to 7480fps with a bullet weight of no less than 165gr and a BC of around .418 to achieve it. Again that is just off the top of my head and I haven't slept in 29 hours so my math could be fuzzy at best. Of course you would have to have a solid non jacketed round. DP Uranium would probably be the best medium for such an undertaking. And more than likely at the minimum you would want a chiropractor on standby but more than likely a good orthopedic surgeon for your shattered shoulder :banghead:

 

[Pete D.]

Roy Weatherby did a bit of work with bullets at the velocities in question.
I remember reading about it in the gun mags...that would have been 45 to 50 years ago.
I do not recall the velocities achieved, though bullet disintegration was the big problem.

 

[Deus Machina]

Anything's possible.

That velocity is doable with some really tough stuff. Someone like Weatherby could probably do it in a weekend, necking down a .50 BMG to .22 and making a strong enough receiver. Will need easily-swappable barrels.

But, to actually travel a mile a second, think reworking everything from the ground up. A rifle too long for a single person to effectively carry to position, a gigantic cartridge, proprietary and amazingly slow powder, proprietary barrel and twist rate, solid bullet, etcetera. Think a heavy-for-caliber round based off the GAU-8. 325gr 7.62x173mm, anyone?

I think it will just be more sound to use airstrikes or amazingly good snipers, until the point we manage fieldable rail- or coilguns

 

[l3uster]

First thing that popped into my head was the .22 Eargesplitten Loudenboomer, but that "only" hit about 4600fps with a 50gr bullet.

 

[John Wayne]

First thing that popped into my head was the .22 Eargesplitten Loudenboomer, but that "only" hit about 4600fps with a 50gr bullet.

At first I thought you were joking. I had no idea that was actually a real cartridge!

 

[kayak-man]

It looks like the biggest problems are keeping the bullet from self destructing, and having a gun that would actually be portable.
For the bullet, what about using a material like steel, titanium, carbonfiber, fiberglass, or something else a little unconventional. how would a Rhinoliner coatet slug work (Not the greatest idea in the world, but its worth throwing out there.)
If the rpm's are what tear the bullet apart, maybe a flesche round with stabilizing fins like what Jubjub posted?

For the platform, I've been looking at some of the bolt action, single shot 50BMG rifles. They aren't much more than a barrel with an action on them. A gun like this isn't going to be used like a 10/22, more like a portable howitzer, so you would not need a magazine. I'm thinking of something like this http://www.serbu.com/top/bfg50.php but set up with a much longer barrel and RPG furniture: Put a shoulder brace/buttstock where the pistol grip is, add a pistol grip and trigger where the forend is.
What do you guys think?

First thing that popped into my head was the .22 Eargesplitten Loudenboomer, but that "only" hit about 4600fps with a 50gr bullet.

That is possibly one of the best names for a cartridge I have ever heard.

Chris "the Kayak-Man" Johnson

 

[rcmodel]

I think Guns & Ammo magazine & ballistician Robert Hutton got slightly over 5,000 with a Weatherly case necked down to .22 or something back in the 60's or early 70's.

That was shooting a plastic pellet "bullet" that weighed next to nothing.
There was no practical use for it, except NASA was using something similar to study cosmic dust collisions on satellites at the time.
In order for NASA to get higher velocitys then that, they had to use a "Rail Gun" that accelerated the projectile with phased electromagnets.

The whole problem of acheaving untra high velocity with smokeless powder is, expanding gases from burning nitrocellulose powder travel at a maximum speed of about 5,300 fps, which is the theoretical velocity limit possible with a firearm.

The other problem is rifling.
In order to produce usable accuray in a normal rifle you have to have it, and the bore friction from it slows down the max velocity possible with smokeless powder even further.

The other problem is bullet weight & sectional density.
Both are necessay to shoot a high-speed bullet accurately any further then just a few yards. And again, a heavy long bullet with low drag is totally counter to reaching ultra-high velocity.

rc

 

[Pete D.]

So it was Horton, not Weatherby, who did the work that I read about in Guns and Ammo.
Thanks for correcting that idea.
Pete

 

[S. Hill]

I think Guns & Ammo magazine & ballistician Robert Hutton got slightly over 5,000 with a Weatherly case necked down to .22 or something back in the 60's or early 70's.

The whole problem of acheaving untra high velocity with smokeless powder is, expanding gases from burning nitrocellulose powder travel at a maximum speed of about 5,300 fps, which is the theoretical velocity limit possible with a firearm.

The other problem is rifling.
In order to produce usable accuray in a normal rifle you have to have it, and the bore friction from it slows down the max velocity possible with smokeless powder even further.

rc

I thought there was something like that, a limit at which smokeless powder simply couldn't expand fast enough. I don't remember where I read it, my grey matter simply has reached it's limit.

 

[Centaur 1]

Let me just throw an idea out there. What if the internet existed 200 years ago. Guys would be writing about how 2000 fps could never be achieved without bullets disintegrating in air, and barrels melting. Wait long enough and new alloys for gun barrels and projectiles will be invented. I'm thinking that a barrel made from an alloy of depleted uranium and tungsten carbide, and bullets made with a solid copper core with a nickel jacket?