Rifle: A machine rated in horsepower

[Vibe]

I always wondered what my avatar sounded like....Now I know.

 

[Vibe]

Maybe the muzzle brake thread should be resurrected, too, since the physics-differently-abled had trouble with that one, too.

Toby Bradshaw
baywingdb@comcast.net

You did ask for it.

 

[tobybradshaw]

You did ask for it.

And now you're asking for it.

You seem to have more patience than I do. Please be charitable to those who think of Newton's Third Law as the Third Suggestion.

Toby Bradshaw
baywinddb@comcast.net

 

[Swamp Fox]

I dirrected a couple of guys from another forum to drop in and see what they thought.

Digital Dan came up with the formula you need.

"Not being schooled in engineering I have none of their structured methodology. Therefore, if a .22 and a .338 Elkinstuffer can both kill a pig I find in favor of efficiency, since the lead and powder consumed by the .338 will, if properly rearranged, kill many pigs. At least 10 times as many. Therefore, the .22 RF is 10 times more efficient. That means the gerbils don't have to work so hard generating those horsepowers. Or pig powers. Chops. That's it, we need a pork chop index!

Ci=D^2(V/BHN)/W-a

Where:
Ci = Chop index
D= bullet diameter
V= velocity in warp fraction
BHN=thickness of cranial plate
W=mass
a=acceleration due to gravity or in a Shelby Cobra

How much pork could a .22 chop if a .22 could chop pork?"


Who said you can't get good info on the net?

 

[Bill Wynne]

Newton's Forth Observation of Motion​

(doesn't quite rise to the status of a law)
​

"It is a wonder of the highest order that some of us know which direction to point a rifle, much less, find the trigger."

Concho Bill

 

[John Kielly]

IHow much pork could a .22 chop if a .22 could chop pork?"

We export a certain number of feral pigs to Europe. They're rank enough, but the European laws require that they be shot (& carry the bullet hole to prove it) for them to be accepted & imported as game meat.

So, they are baited into large weldmesh traps, maybe emough room for 50 odd of them, with carrion baits, then put out of their misery & onto a German plate with a .22 rimfire shot to the head.

 

[Vibe]

Please be charitable to those who think of Newton's Third Law as the Third Suggestion.

Toby Bradshaw

Now there is a fairly apt analogy.

Newton's Forth Observation of Motion​

(doesn't quite rise to the status of a law)
​

"It is a wonder of the highest order that some of us know which direction to point a rifle, much less, find the trigger."

Concho Bill

Dang Bill. I have to give you that one.
That has got to be, hands down, one of, if not THE most accurate post you've made in this thread.

 

[longshooter]

Now there is a fairly apt analogy.

Dang Bill. I have to give you that one.
That has got to be, hands down, one of, if not THE most accurate post you've made in this thread.

Hopefully, he feels better now!


Longshooter

 

[Old Gunner]

Remembered another instance of a cartridge used to turn an engine, the starter cartridges used for some radial engines. They look more like a large shot shell sized blank cartridge.

According to hollywood a rifle shot can lift a Homeboy off his feet and throw his body through a plate glass window. So studying the film we might estimate the weight and velocity of said Homeboy and then calculate just how much energy in terms of Homeboys per foot is contained in an AK 47 magazine. Start off with X number of HPF per AK/M = ?.
Eliminating Gang Bangers being the useful work of the equation.

 

[Vibe]

Remembered another instance of a cartridge used to turn an engine, the starter cartridges used for some radial engines. They look more like a large shot shell sized blank cartridge.

Reference the movie "Flight of the Phoenix".

 

[moemag]

Vibe,
I still stand by my stock horsepower calcs...
as far as bullet horsepower, I will apolgize and say your ~3600hp is right.

I can't find any way around it hahaha! I really wasnt expecting it was going to be that high.

Cheers. It was fun.

 

[Vibe]

Vibe,
I still stand by my stock horsepower calcs...
as far as bullet horsepower, I will apolgize and say your ~3600hp is right.

I can't find any way around it hahaha! I really wasnt expecting it was going to be that high.

Cheers. It was fun.

Your "Stock HP" may also be correct...for the few thousandths of inch that it's powered. While the Momentum of the stock is equal to the momentum of the bullet and gasses, the energy is not, so the change in energy is not the same - therefore the HP cannot be the same. Quite frankly I'd never thought to look at the HP from the perspective of stock movement. But, like you, I was a bit surprised at the disparity.

Yes. It has been fun.

Now..If you'd care to jump into the Muzzle Brake thread, that one looks to have equally interesting "debate".

 

[Bill Wynne]

I respectfully submit one more time that the work done by a 220 grain bullet with a muzzle velocity of 300 feet per second is way less than one horsepower.

Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute (550 foot pounds / second). Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy.

Newton's third law of motion states for every action there is an equal and opposite reaction. Therefore: The weight of the bullet X it's velocity is equal to the weight of the rifle X it's velocity. They are exactly the same.

220 grain bullet = .0314 pounds (a good sized bullet)

.0314 pounds X 3000 feet per second = 94.2 foot pounds per second

94.2 foot pounds per second / 550 foot pounds per second =.1712727 and that is how much horsepower is produced. You can make this more complicated but you cannot make this more correct.

I know this to be true from my long ago study with a ballistic pendulum.

Consider this. No mortal man could withstand the impact caused by thousands of horsepower. Superman? Maybe.

Concho Bill

 

[Vibe]

I respectfully submit one more time that the work done by a 220 grain bullet with a muzzle velocity of 300 feet per second is way less than one horsepower.

You have now had two people with engineering degrees tell you different. If you STILL chose to remain ignorant, it's now all on you.

Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute (550 foot pounds / second). Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy.

Newton's third law of motion states for every action there is an equal and opposite reaction. Therefore: The weight of the bullet X it's velocity is equal to the weight of the rifle X it's velocity. They are exactly the same.

This is true, however that is a statement of conservation of Momentum. The Energy is NOT similarly conserved.

220 grain bullet = .0314 pounds (a good sized bullet).

We'd been using 200, but what the heck.

.0314 pounds X 3000 feet per second = 94.2 foot pounds per second.

0.0314 under the influence of the acceleration of GRAVITY (32/ft/sec/sec)
Under the influence of the Acceleration due to Rifle this is 72.22 pounds.



I'v got to go to work now, so I'll get to the rest tomorrow.

 

[pacecil]

To Bill Wynne.....

you calculated:

220 grain bullet = .0314 pounds (a good sized bullet)

.0314 pounds X 3000 feet per second = 94.2 foot pounds per second

The pounds in the units of ft-lbs/sec is not the weight of the bullet. It's the pounds force you applied in accelerating the bullet up to 3000 fps
Also the feet in the units is not the feet in 3000 fps. It's the ft you moved the bullet thru to get it up to 3000 fps.

Multiplying the weight of bullet by it's velocity at the muzzle will not give you the work done on the bullet when you accelerated it out the barrel. You get this by multiplying the force applied over the distance the bullet traveled and then dividing by the time the force was applied. The force is constantly changing as the bullet travels up the barrel, which is why you must integrate or use an average.

 

[Bill Wynne]

You have now had two people with engineering degrees tell you different. If you STILL chose to remain ignorant, it's now all on you.

Respectfully, we can disagree and not be disagreeable.

Not to make this personal, Vive, but on any test at the school of engineering that you attended did you miss any question?

What I am saying is that even people with engineering degrees are sometimes in disagreement. Could it be that you and others have complicated a simple definition of a horsepower into something James Watt would not recognize?

Concho Bill

 

[pacecil]

To Bill Wynne...

You asked: Could it be that you and others have complicated a simple definition of a horsepower
This doesn't appear to be the problem. What is happening is you are simply not doing it right. What you have calculated as work, from which you will later calculate horsepower, is not that at all - it's momentum. This is an understandable error because momentum and work would appear to have the same units, ft-lbs/sec (or lb-ft/sec) You do work when you apply a force to a body and move it a distance in a period of time. In the units ft is the distance, lbs is the force and sec is the time.

A 200 grain bullet traveling at 3000 fps can only do work or have work done on it during the time it travels some distance. If it travels in a vacuum it will do no work nor will it have any work done on it. If it travels in air, the air will do some work on the bullet as it slows the bullet down. At the same time the bullet will be doing work on the air as it moves the air out of the way.

 

[Vibe]

Respectfully, we can disagree and not be disagreeable.

Not to make this personal, Vibe, but on any test at the school of engineering that you attended did you miss any question?

LOL. Yep...But not this one.

What I am saying is that even people with engineering degrees are sometimes in disagreement. Could it be that you and others have complicated a simple definition of a horsepower into something James Watt would not recognize?

Concho Bill

I will freely admit that my numbers are not completely accurate, but that is due to the fact that I have simplified the math to the point that the Integral Calculus required to accurately determine the true and actual acceleration has been reduced to a simple averaging of velocity -other wise the HP number would really be quite a bit higher. The actual time in barrel is a bit less than my "estimate". Your new 220 grain bullet at 3000 fps from a 26" barrel would more likely be applying closer to 6000HP to the bullet.

Which brings me to another point. You keep refering to work done by the bullet.

I respectfully submit one more time that the work done by a 220 grain bullet with a muzzle velocity of 300 feet per second is way less than one horsepower.

We are not concerned with this because it was not part of the quetstion. This "work done by the bullet" is just he bullet bleeding off all of the energy that we applied to it during the firing process.

 

[moemag]

engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.
- dr ar dykes -

:d

 

[Vibe]

Now that is accurate enough.
And would describe the practices of most of the engineers I've come in contact with my modest career.