5000 fps...and if so...why?


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Redlg155
April 24, 2012, 08:33 PM
I was looking through my newest Lee reloading manual and noticed that I did not see a load over 5000 fps or so. The fastest listed is a 20gr bullet at approx 4600 fps.

Does anyone make a heavier, lets say 55 grain bullet at 5000 fps, and if so, are there any practical uses?

What's theoretical or proven speed limit before bullets explode in flight?

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igousigloo
April 24, 2012, 09:21 PM
I think you just found it.

rcmodel
April 24, 2012, 09:25 PM
It's not the bullets that limit the speed.

It's the burn rate and expansion ratio of smokeless powder.

The fastest you can shove a projectile of any weight of any construction, is limited by how fast expanding powder gas can push it at safe pressure limits.

5,000 is about it with known smokeless powders we have available to us.

rc

45_auto
April 24, 2012, 09:55 PM
You can crank the velocity up until the air friction burning up the projectile becomes a problem, you just have to build a heavy enough barrel to contain the pressure.

They passed 50,000 fps with a 15 grain bullet about 20 years ago, I don't know what the record is now.

http://www.nytimes.com/1994/03/22/science/fastest-gun-on-earth-goals-go-beyond-planet.html

rcmodel
April 24, 2012, 10:02 PM
compressing hydrogen gas in the chamberBut like I said, smokeless powder available to manufactures and handloaders is the limiting factor, not the bullets.

Rail guns and particle accelerators can shoot very small things even faster.
But they use electrons, not smokeless powder.

rc

General Geoff
April 25, 2012, 12:43 AM
I've always thought a tiny amount of high explosive such as trinitrotoluene would make for a superb propellant in a shoulder fired small arm, in order to propel a projectile far faster than smokeless powder allows. Unfortunately the pressures involved would require much sturdier construction than is typically found in modern small arms.

56hawk
April 25, 2012, 01:29 AM
QuickLoad predicts I can get around 5000 fps by shooting 97 grain aluminum bullets out of my 460 Weatherby. I'm really tempted to buy some and give it a try.

Here is a link to the bullets: http://lehighbullets.com/products.asp?cat=32

MachIVshooter
April 25, 2012, 01:50 AM
Smokless propellants expand at a maximum rate of about 6,000 FPS. Of course, you have to account for friction, so the limit on small arms bullet speed using smokeless propellants is a bit slower, around 5,200-5,300 FPS.

This is why modern artillery is smoothbore; The 120mm sabot KE penetrator rounds like the KEW-A1 are cookin at about 5,700 FPS.

It takes explosives or electromagnetic propulsion to go faster. Electromagnetic railguns can hit 35k FPS last time I looked, probably more by now.

Jim Watson
April 25, 2012, 02:08 AM
"I've always thought a tiny amount of high explosive such as trinitrotoluene"

That's been tried with mercury fulminate, nitrocellulose, and nitroglycerine. Those folks soon found that you do not want a shock wave as produced by a true explosive. Even a little of it.

The propellant for the caseless H&K G11 is/was allegedly a denatured explosive rather than a conventional propellant but the key word is denatured. It had explosive chemistry but had been toned down to deflagrate instead of explode.

fireman 9731
April 25, 2012, 04:14 AM
Lehigh Bullets makes some amazing stuff....

45_auto
April 25, 2012, 05:46 AM
But like I said, smokeless powder available to manufactures and handloaders is the limiting factor, not the bullets.

Rail guns and particle accelerators can shoot very small things even faster.
But they use electrons, not smokeless powder.

Did you bother to read the article? They do discuss rail guns early in the article, but the one that is the one under discussion uses "a charge of burning powder" to drive the first stage up to about 150,000 PSI. I doubt that it is black powder. Any handloader with sufficient resources (maybe Bill Gates?) could build the same type of staged compression gun to get extremely high velocities, it's a simple pressure vessel. The secret to it is the way they apply the impulse to the projectile.

From http://www.nytimes.com/1994/03/22/science/fastest-gun-on-earth-goals-go-beyond-planet.html

In the first barrel, 3.5 inches in diameter, a charge of burning powder drives a heavy plastic piston down the bore, compressing hydrogen gas in the chamber ahead of it. When the hydrogen reaches a pressure about 10,000 times that of the atmosphere, a barrier disk ruptures and the hydrogen blasts into the second barrel, one inch in diameter, to drive another piston.

Walkalong
April 25, 2012, 07:19 AM
His point remains valid to the OPs question.

gym
April 25, 2012, 11:03 AM
Talk about fast, the Air force and Navy, have a 12,000,00 mph hyper engine jet, it flies 20 times the speed of sound, NY to LA in 12 minutes. Problem is they keep blowing up, I think they lost 2 so far, what a weapon system that is when they get it right. They said that the paint peeled off the wings.

Ryanxia
April 25, 2012, 11:29 AM
Dam I have to take a better look at my new Lyman reloading book. That's a screamin velocity!

brickeyee
April 25, 2012, 11:52 AM
"but the one that is the one under discussion uses "a charge of burning powder" to drive the first stage up to about 150,000 PSI. "

You mean the ny times has finally discovered what a light gas gun is?

The problem is that they are not all that useful.

We have used them for many years to simulate objects impacting satellites.

45_auto
April 25, 2012, 11:56 AM
You mean the ny times has finally discovered what a light gas gun is?

The article is from 1994 .....

But they've probably forgotten all about it by now!

Blanco
April 25, 2012, 11:59 AM
Didn't the old Remington .17 get real close to 5k?
My grandad used a .17 Remi bolt gun for turkey .... Just aim for the head. It usually vaporized it.

alsaqr
April 25, 2012, 12:25 PM
The 120mm tank gun attains a velocity of 5,500 fps using the APFSDS-T round. There is no metal cartridge case; just a stub base with primer.

http://www.inetres.com/gp/military/cv/weapon/M256.html

ldsgeek
April 25, 2012, 12:53 PM
Not the paint but the actual skin of the craft. Bernoulli really messed up that design for them.

Jim Watson
April 25, 2012, 02:48 PM
Yup.
As Jerry P said of the test, it just goes to show why the ramjet-rocket ground to orbit ship is not a good idea. You do not want to go hypersonic in atmosphere very much.

moxie
April 25, 2012, 03:46 PM
It's well known in certain circles that a classified small amount of micropulverized unobtainium electrically bonded to granules of certain powders will permit velocities in excess of Mach 7. The problem is that everyone within 1500 meters dies, unless they get out of the area quickly in their scramjet.

Redlg155
April 25, 2012, 04:48 PM
Ok...but what do we get when use the following criteria?

1. Weapon must be shoulder fired and man portable. A .50 cal Barrett is man portable, so that leaves some room for a heavier weapon.

2. Able to use a cartridge case to comtain whatever firing compound used.

3. Somewhat capable of accuracy.

I for one would like to see a .50 BMG case necked down to about 6mm/.243.

fireman 9731
April 25, 2012, 11:00 PM
Or a 50 BMG necked down to 17 caliber....

http://pictures.gunauction.com/9121103213/10641911/dscn2450.jpg_thumbnail0.jpg

I got up to 4400 FPS(chronographed) with my 22-250 using 36 grain Barnes Varmint Grenades and Varget. Its right at the the top of max published load data. It couldn't be that hard to squeeze 600 more fps out of something similar.

-v-
April 25, 2012, 11:09 PM
Dude, that's photoshopped right?

firesky101
April 25, 2012, 11:52 PM
I hope not, please tell me you are planning a test rifle fireman

I am thinking like 2 shots before the barrel is shot out.

MachIVshooter
April 26, 2012, 12:33 AM
Didn't the old Remington .17 get real close to 5k?

4,400-4,500 is about it.

The .17 Rem, .204 Ruger, .223 WSSM and .220 Swift are the fastest commercial rounds out there, running 4,000-4,500, depending on bullet weight and barrel length. Anything faster is so overbore that throat life is in the hundreds at best. A few wildcats and a couple of the Lazzeroni cartridges can push light-for-caliber bullets to ridiculous velocities as well, but still quite a bit short of 5,000.

The .22 Eargesplitten Loudenboomer (yes, it's real) hit 4,800, IIRC.

Weatherby did push over 5,000 with the .30-378 using custom 60 grain bullets.

.50 BMG firing .308 bullets in sabots have also been pushed to 5,200.

These and other such hyper-velocity attempts require very long barrels to achieve their numbers.

There just comes a point when all you're really doing is burning more powder, increasing chamber pressures and turning the throat into vapor.

fireman 9731
April 26, 2012, 02:40 AM
Haha no, I think its a real picture, and I think the 50-17 wildcat is real. More of a novelty than anything. In the picture it looks the case has a spent primer in it. I have seen other pictures though besides that one.

Flopsweat
April 26, 2012, 07:49 AM
The 120mm tank gun attains a velocity of 5,500 fps using the APFSDS-T round. There is no metal cartridge case; just a stub base with primer.

http://www.inetres.com/gp/military/cv/weapon/M256.html
OT, but they make a giant buckshot round in this caliber. Near the bottom of the page:


The 120mm M1028 Canister is a muzzle action anti-personnel tank cartridge. This cartridge is fired from the 120mm main gun of the M1A1/M1A2 Abrams tank and is effective at ranges less than 700 meters. The baseline design utilizes a payload of approximately 1,100 tungsten balls that are expelled from the projectile casing upon muzzle exit, similar to a shotgun shell.

Unlike previous antipersonnel cartridges, the M1028 does not have a fuze; it is intended to be a low-cost, low-technology cartridge.

The M1028 uses a combustible cartridge case and propulsion-ignition system common to the current 120mm tank ammunition.

This is a training standard item used in both training and combat.

Type Classification Date: December 2004. Unit cost: $2,000 (Fiscal Year 2009).
¦Length: 30.67 in (779 mm)
¦Weight: 50.51 lb (22.9 kg)
¦Projectile Color: Olive drab with white markings.



Yowza. They do not list a muzzle velocity, but with a 700m range, it's got to be bookin'.

CB900F
April 26, 2012, 11:02 AM
Fella's;

If I remember correctly, the American Rifleman published an article within the last ten years or so on the government experimental hyper-velocity guns. And, as was stated previously, the purpose is to simulate satellite impacts with either space debris or as a target.

900F

brickeyee
April 26, 2012, 02:53 PM
The article is from 1994 .....

Light gas guns predate even 1994.

1858
April 26, 2012, 04:16 PM
A large caliber sabot can be used to propel a smaller caliber bullet at 5,000+ fps with existing powders. It'd be interesting to play with a .338 LM sabot and shoot an 80gr .223 bullet out of the muzzle at 5,500 fps. It'd probably need to be a solid bullet or at least bonded to keep the jacket on ... but maybe not.

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