What would happen?

B

bluechip

Guest
Let's take a bmg 50, 750 grain bullet for an example. It is said to have excellent B.C. Now, if the bullet were to retain the same weight of 750 gr and be .25 in dia, it would have 1/4 the wind drag and seemingly have very good ballistic qualitys. This could be done by streching a .25 out to maybe 4" long. I would think that side drag is small compared to frontal resistance. Has anyone heard of anything like this being done?
 
No, I have not. One reason that it is unlikely is the rifling twist rate that would be required to stabilize a projectile with such an extreme length to diameter ratio. There are other major theoretical problems as well.
 
Longer bullets

I would guess comparing the the lightest .308 bullet to the heaviest .224 bullet would be a similar concept because the BC would be about 3X higher for the longer .224 bullet and required twist would be about 2X as fast. nhk
 
Hmmm maybe some thoughts

I havent plugged what it would take twist wise to stabilize a 25 caliber bullet but the long 22s are taking what down to 7twist? How long would a 25cal 750gr bullet be? If it took a much faster twist and the bullet was say over 4 inches then torsional forces would act to shear the bullet and engraved rifling. Result distorted bullet. In other words a long bullet would be twisting in the front while the base was still in the case, then rifling itself could introduce a shear, same at the muzzle where the long projectile front would be in air and the rear in the rifling. And I might suspect that like an arrow you might get a sine curve movement like an inch worm on the long projectile as it went through the atmosphere. Then there would be the friction of such a long thing going down the bore and the amount of force applied to the tiny back end to get it launched at getty up speed. Probably some burning and distortion there. How about the rocket bullet? STBE
 
Your 4 inch bullet would require a twist rate of about 1/3. Thats not one third, its one turn every three inches, or there abouts. Try this link, a bit more user friendly. http://www.uslink.com/~tom1/twistrate.htm. Looks impossible to me for the above stated reasons.

Donald
 
okay

All that replied have made some valid points. If it were feasible, I'm sure something so simple would be commonplace. I guess it sounded good until one took a 'look under the hood'. Maybe when physicists come up with a material that is inexpensive and outweighs lead by a factor of 4 or 5 we'll talk again.
 
Only javelin type bullets in use that I know off are the specialized underwater projectiles used by Russian Spetnatz and other commando weapons designed for amphibious assaults.

You might look these up, but I'm not sure they even use rifled bores.
 
Instead of...

bluechip said:
Let's take a bmg 50, 750 grain bullet for an example. It is said to have excellent B.C. Now, if the bullet were to retain the same weight of 750 gr and be .25 in dia, it would have 1/4 the wind drag and seemingly have very good ballistic qualitys. This could be done by streching a .25 out to maybe 4" long. I would think that side drag is small compared to frontal resistance. Has anyone heard of anything like this being done?
Click to expand...

Instead of this extreme length choice, substitute a tungsten core...maybe...:rolleyes:
 
bluechip said:
Let's take a bmg 50, 750 grain bullet for an example. It is said to have excellent B.C. Now, if the bullet were to retain the same weight of 750 gr and be .25 in dia, it would have 1/4 the wind drag and seemingly have very good ballistic qualitys. This could be done by streching a .25 out to maybe 4" long. I would think that side drag is small compared to frontal resistance. Has anyone heard of anything like this being done?
Click to expand...

The bullet would be about 4.35 times as long. Think of a pencil.
Can you imagine the pressure to get the thing out of the end of barrel?

Concho Bill
 
If you are still hung up on the loooonng bullet thing, think of a dart with a sabot. Kind of like that army tank long rifle that shoots a sabot dart at close to 10,000 fps. This is in a smooth bore tube. If my momory is still reasonably intact, always a question.:(

Donald
 
Bill Wynne said:
The bullet would be about 4.35 times as long. Think of a pencil.
Can you imagine the pressure to get the thing out of the end of barrel?

Concho Bill
Click to expand...

Bill, I think you nailed it, the pressure acting on the same weight (750 gr ) and pushing on an area 1/4 the size would have to rule it out. BTW, I remember reading an old Guiness world record book the had the highest rifle muzzle velocity on record by the military I believe. I'll find the old book and see, but it seemed like it was either 5000 or 7000fps.
 
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