Rifle: A machine rated in horsepower

[Bill Wynne]

"engineering is the art of modeling materials we do not wholly understand, into shapes we cannot precisely analyze 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."

Good statement Moemag. I like your humor.

Let me add from my observation of engineers and their projects:

There two schools of engineering in the world.
Those who designed the pyramids and those who designed the Golden Gate Bridge. One uses the most materials that can fit into the space and the other uses the least materials that will adequately do the job.

Vibe,

Sorry about what I said about that bullet and work. You know the by the bullet. How about to the bullet. There now, I feel better.

Concho Bill

 

[Vibe]

Vibe,

Sorry about what I said about that bullet and work. You know the by the bullet. How about to the bullet. There now, I feel better.

Concho Bill

No apology required, I'm just trying to discover the source of your confusion and why this is so difficult for you to grasp. You're as hard headed and argumentative as I am.
But the bullet does exhibit a bare minimum of horsepower in flight (at least until it hits a solid target), and if that had been why you thought as you claim to, we could have addressed it.

 

[Bill Wynne]

No apology required, I'm just trying to discover the source of your confusion and why this is so difficult for you to grasp. You're as hard headed and argumentative as I am.
But the bullet does exhibit a bare minimum of horsepower in flight (at least until it hits a solid target), and if that had been why you thought as you claim to, we could have addressed it.

Don't worry about it Vibe. I have my story and I am sticking to it.

I have fired a 300 H&H Magnum Ackly Improved* into a 14 pound ballistic pendulum** and it swung out and lifted up a few inches at the most. Very loud report, healthy recoil, but very little horsepower.

* 150 grain bullet, MV = 3500 feet per second more or less.
** This was a steel pipe full of sand with a piece of rubber inter tube over the end of the pipe with cotton behind it. The pipe was hanging by two light weight wires.

Note: I was maybe 19 years old. I have lived 50 additional years. I must have been a little crazy.

Concho Bill

 

[moemag]

Picked this up about an hour ago

I have some reading to do


I will get back to this, and muzzle brakes in a few days.

 

[Vibe]

I have fired a 300 H&H Magnum Ackly Improved* into a 14 pound ballistic pendulum** and it swung out and lifted up a few inches at the most. Very loud report, healthy recoil, but very little horsepower.

* 150 grain bullet, MV = 3500 feet per second more or less.
** This was a steel pipe full of sand with a piece of rubber inter tube over the end of the pipe with cotton behind it. The pipe was hanging by two light weight wires.

Note: I was maybe 19 years old. I have lived 50 additional years. I must have been a little crazy.

Concho Bill

Ballistic pendulums are neat and interesting, but have nothing to do with HP - they only measure momentum.
The one I built was only 3 lbs, but I was using 30 to 35 gr bullets at less than 2000fps. At 85" the pendulum was "calibrated" to swing almost exactly 1" for every 100 fps. (Made the math easier)

 

[Bill Wynne]

Ballistic pendulums are neat and interesting, but have nothing to do with HP - they only measure momentum.
The one I built was only 3 lbs, but I was using 30 to 35 gr bullets at less than 2000fps. At 85" the pendulum was "calibrated" to swing almost exactly 1" for every 100 fps. (Made the math easier)

The size of yours was good thinking. You could demostrate the same results as I did with a pellet gun in your garage without near the danger. I tested four different centerfire cartridges with mine and the results were very close to their know velocities. I tested a .222 Remington, a 25/06 Ackley Improved, a 30/06 and that 300 H & H Ackley Improved.

How does this relate to our problem at hand?​

To obtain the velocity of the projectile striking the pendulum, the movement of the ballistic pendulum against the force of gravity is measured in units of mass divided by distance such as foot/pounds. 550 foot/pounds per second = 1 HP.

You have a known weight of projectile and a known velocity in feet per second. Convert what you know to foot pounds per second and divide that number by the number of foot pounds per second that are one horsepower (550) and that is the horsepower developed by your rifle and transfered to the projectile or bullet.

It is no more complicated than that.

Concho Bill

 

[Vibe]

How does this relate to our problem at hand?​

To obtain the velocity of the projectile striking the pendulum, the movement of the ballistic pendulum against the force of gravity is measured in units of mass divided by distance such as foot/pounds. 550 foot/pounds per second = 1 HP.

You have a known weight of projectile and a known velocity in feet per second. Convert what you know to foot pounds per second and divide that number by the number of foot pounds per second that are one horsepower (550) and that is the horsepower developed by your rifle and transfered to the projectile or bullet.

It is no more complicated than that.

Concho Bill

You are right, it really is no more complicated than that. However - for the HP being applied to the bullet by the rifle what you have is the Ft-Lbs of energy of the bullet at the muzzle divided by the time it took to get it up to that speed. And for out 200gr bullet at 3000ft/sec that is a muzzle energy of around 4100ft-lbs( use the published data from the manufacturer, or an energy caculator in a load manual), and it took 0.001444 seconds to clear the 26" barrel (Distance traveled, under the applied force, divided by the average velocity).

So...What do you get when you divide 4100 ft/lbs by 0.00144 seconds?

4100/0.001444 = How many ft-lbs/sec?

And dividing that number by 550 gives you how much HP?

 

[Bill Wynne]

Vibe, It doesn't matter that some work is done quickly. That amount is all the ever done. Wait a second before you calculate how much horsepower was applied. There would be a lot of horsepower if the initial powder charge could keep up for a full second but it can't.

Why? Because it just doesn't have enough power (horsepower that is).

I think I know why we just look at the bullet weight and bullet velocity and don't ever mention the horsepower.

Concho Bill

 

[pacecil]

To Bill Wynne...

You said You have a known weight of projectile and a known velocity in feet per second. Convert what you know to foot pounds per second and divide that number by the number of foot pounds per second that are one horsepower (550) and that is the horsepower developed by your rifle and transfered to the projectile or bullet.

This is WRONG! Read my posts 233 and 235! You think that if your answer is to be in ft-lb/sec you can use any thing you have in front of you with these units and this will make your answer right. You cannot use bullet weight for the lb in the units. The lbs has to be the gas pressure force in lbs. You cannot use the ft from the fps velocity. This ft unit has to be the barrel length in ft, that is the distance over which you were adding work to the bullet.

You can't get horsepower from a bullet at a single point in space. You have to decide over what distance of travel you want to determine the horsepower was expended.

 

[Vibe]

Vibe, It doesn't matter that some work is done quickly.

Other than that is exactly what the definition of "Power" is, and that we like barrels shorter than 1300" to get up to a useful velocity.

That amount is all the ever done. Wait a second before you calculate how much horsepower was applied. There would be a lot of horsepower if the initial powder charge could keep up for a full second but it can't.

Nothing in any physics book ever indicated that time HAS to be measured only in full second intervals. (Good thing too, or lasers would be useless)

Why? Because it just doesn't have enough power (horsepower that is).

If it COULD maintain that level of power for a full second, it would seriously maim the shooter. Even 16" naval guns don't take a full second to go off.

I think I know why we just look at the bullet weight and bullet velocity and don't ever mention the horsepower.

Concho Bill

The obvious answer is that the HP value is so esoteric as to not be of any real relevance to everyday life. But the question was asked, I answered factually...You argued.
And here we are.

 

[Bill Wynne]

But the question was asked, I answered factually...You argued.
And here we are.

Yes, Here we are!

Your facts have confused you. I am sorry. I am content to leave you there with your thoughts but I feel the need to shed the light of truth on the subject so others will not be lead astray.

If we ever meet, I will buy you a cup of coffee but we must not discuss horsepower or rifles.

Concho Bill

 

[pacecil]

Bill Wynne says I feel the need to shed the light of truth on the subject so others will not be lead astray

That's ok, but the light you are shedding is simply not true!

 

[Bill Wynne]

I think I see your problem

Look Pacecil and Vibe. The need for the unit of power called "Horsepower" was devised a long time ago when engineers were not as smart as they are now. Think about it, Why would anyone try to compare the power of a steam engine with the power of a horse. That fellow was not the sharpest pencil in the box but he did the best he could. He did not even have a computer to help him with his calculations. He did all this in an age before long division was clearly understood.

He had to keep it simple or else the math would have eaten him up hair and all.

You guys are way smarter than that guy so you can make it far more complicated than he could handle.

A simple man can do just so much. Because I am simple too, I understand the problem and can reach the conclusion.

Concho Bill

 

[pacecil]

Hey Bill....

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.
A 150mph is 220 fps. The car weighs 2500 lbs.
2500 X 220 will give us 550000 ft-lbs/sec.
And then we'll divide that by 550 to get horsepower.
Gives us 1000hp!
That seems like a lot of power from that little four cylinder engine. What did I do wrong?

 

[Bill Wynne]

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.
A 150mph is 220 fps. The car weighs 2500 lbs.
2500 X 220 will give us 550000 ft-lbs/sec.
And then we'll divide that by 550 to get horsepower.
Gives us 1000hp!
That seems like a lot of power from that little four cylinder engine. What did I do wrong?

You got me there. That is a great car.

I am going to have to let you have that one on shear cleverness.

The only thing that I could think of is that your car would have to lift 2500 pounds 220 feet in one second after overcoming the initial effects of inertia to exhibit 1,000 horsepower. What do you think?

Concho Bill

 

[Vibe]

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.
A 150mph is 220 fps. The car weighs 2500 lbs.
2500 X 220 will give us 550000 ft-lbs/sec.
And then we'll divide that by 550 to get horsepower.
Gives us 1000hp!
That seems like a lot of power from that little four cylinder engine. What did I do wrong?

Same thing Bills been doing. Trying to equate Momentum with power, and Lbs weight with Lbs Force. How fast will it get to 150mph?

Bill has come to his simple conclusion, and it doesn't seem to bother him in the least that that conclusion is incorrect.

 

[Bill Wynne]

Bill has come to his simple conclusion, and it doesn't seem to bother him in the least that that conclusion is incorrect.

I am comfortable with my opinion. Why would I need yours?

That's my story and I am sticking to it.

Concho Bill

 

[Vibe]

I am comfortable with my opinion. Why would I need yours?

That's my story and I am sticking to it.

Concho Bill

LOL. I don't suppose that you would need my "opinion", but my position in this matter is more than mere opinion, it can be proven and reproduced through experimentation. Your position cannot be.

 

[pacecil]

Bill....

You remarked: The only thing that I could think of is that your car would have to lift 2500 pounds 220 feet in one second after overcoming the initial effects of inertia to exhibit 1,000 horsepower. What do you think?

I'm not sure why but you did ask what I think. You seem only able to comprehend horsepower as a "lifting" action, so I'll just go along with you. You can use what I'm about to say any way you want, that is you can try to understand it, or you can ignore it as you have mostly done in the past.

I won't go into the calculations required because you would simple ignore them. Here's all I'll say: You must determine how much force you need apply to underside of car to cause it to accelerate from zero fps up to a speed (This turns out to be 440 fps.) necessary to get the car 220 ft up in the air in one second. You must multiply the acceleration times the weight (mass) of the car to get the required force. (Force =Mass X Acceleration or F=Ma. This tiny equation governs your entire life. You better believe this even if you don't believe anything else!) If you do all this you arrive at a force of 19687 lbs, (Note, you don't just have "initial inertia" - you got it all the way up!)

Now comes the part where we leave you - determining the horsepower it requires to do this lifting. If we apply that 19687 lbs force all the way up to 220 ft and do it in one sec we will do 4331140 ft-lb/sec of work. This is equivalent to 7874 horsepower. So that's what it takes to lift 2500 lbs 220 ft in one second. (Back to that inertia thing - almost 90% of the work done here is overcoming inertia of the moving weight. The other 10% is just to lift the weight up off the ground.) ( I decided to add this maybe to make you feel better about your 1000hp: If you wanted to just lift the car very slowly up off the ground, you could do this with about 800 hp.)

Now I know this doesn't compare to your method of multiplying 2500 lbs times 220 fps and dividing by 550 to get 1000 hp. But just study and think about it for a while

 

[Bill Wynne]

Lynn,

Thank goodness you stepped in. Let me explain. I am being boxed about by two sharp minded engineers. They have ganged up against me but I am about to outsmart them. (Be sure to read to the bottom.) You can be an honest, non-bias, independent broker and listen to my the facts. Please bear with me.

The history of the term horsepower: In the last quarter of the 18th century James Watt while trying to sell his steam engine was searching for a way to explain the power it could produce. In those days horses were common. Everyone moved about and did work with horses so he sought to explain the power of his engine against the work that a horse could do.

He studied what amount of work could be done by a mill horse who walked around an 12 foot circle moving a millstone. These horses were draft horses not riding ponies. They were powerful animals. He determined that a horse could pull with a force of 180 pounds for his whole shift. At the rate the horse walked that amounted to of 33,000 foot pounds per minute or 550 foot pounds per second. This means the horse could lift 550 foot pounds per second for a long time. Mr. James Watt used that as the definition of one horsepower. (1 horsepower = 33,000 foot pounds per minute = 550 foot pounds per second)

You see, Lynn, this was an very unusual definition by today's standards but it is based on an factual observed events. If you will notice it says nothing about kinetic energy or the square of anything. It is a simple definition that simple men would understand. Engineers by their nature complicate the simple because that is what they do.

Lynn, I have given you the definition of a horsepower that James Watt gave people in his day. Take any rifle and any bullet at any given muzzle velocity and see what you come up with.

Going back to the Montana Pete's question.
This was his question: "Can you take a specific cartridge in a specific rifle and determine the horsepower generated by the rifle?"

Without going into detail, the answer to that question is yes.

Concho Bill