Where does the energy go?

[TKelly]

Hey there Just J,

In a vacuum or in the absence of air, both projectiles would arrive at identical horizontal distances. Therefore, they would both have the same range.

However, since we're dealing with a realistic scenario here, the spinning round ball will experience less drag due to gyroscopic angular momentum or rotational motion. Since the rifled round ball is the spinning round ball, it will have a decidedly longer range than the round ball launched from the smoothbore.

 

[kelleyjk]

Oh yeah? Says you! What if theyre both fired underwater huh?

:wink:

 

[TKelly]

Like I've already stated, the one spinning, goes further, says me!LOL :rotf:

 

[TKelly]

No worries, you're a great guy! :v

 

[longcruise]

I could almost agree with you if black powder burned progressively if the powder choosen properly meaning the fast powders with lighter ball and the slower powders with the heavy ball there would not be that much unburnt powder on the ground. OK back to speed vs rifling since blackpowder does not burn progressively the black powder doesn't build pressure as does modern powders it only has so much push and when the black powder burns out in the barrel there is no increase in pressure. With black powder upon ignition as the ball travels down the barrel the pressure will go down because of the pressure chamber ( the barrel) increases and the inside pressure (Expanding gases) begin to take up the area made behind the ball then pressure begins to fall and because it has burnt the powder there is no increase in speed you can't apply modern powders physics to black powder is doesn't work the exactly same way All things being equal the smooth bore should have a higher muzzle velocity

Nope just does not work that way. I and others have proven it with chronographs. What happens with a rifled barrel is that the smoother the bore becomes (not reduction of rifling, but just making the surfaces smoother) the slower the ball flys. IOW, a rougher bore that is more resistant to putting the ball in motion will end up with more MV. This can be demonstrated by chronographing a roughish barrel and then lapping it smooth. Once lapped it shoots slower. And "no", it's not because it is enlarged.

You can find the same effect by everincreasing the tightness of patch material. The tighter it gets the faster it shoots! Same effect when using a less and less slick patch lube. Less slick lube shoots faster. Very obvious when you compare a greased patch and the same combo lubed with the "dry patch" (or Dutch's system). Dry patch is faster every time.

I don't know if rifling will produce the same effect. How would it be tested? Comparison of an .xx cal rifle with identical .xx cal smoothbore tells you nothing. That is easy to see when you see the range of possible variations in velocity from "identical" rifles.

And, on top of that, none of this has anything to do with the original question posed in the first post.

In fact, the original question is so poorly stated it is not even clear what the question is. Neverthless, we manage to generate many pages of posts filled with artless mumbo jumbo. :rotf:

 

[Danbo]

Danbo, theres very little if any irregular imbalance in the laminar flow, concentricity or any other big words on my 7.62 Sierra Matchking 168gr boatail round, but as good as that bullet is, if it aint spinnin, I aint hittin an Abrams M1 even at 500 metres

as to a round ball yep theyre irregular, especailly cast balls tend to have more mass on one side than a swager, still gyroscopic stabilization does occur (even if it dont "yaw" like a pointy bullet)

Ok so if I have miss understood you KH its still a valid question

which one goes farther?

.58 ball spinnin
.58 ball not spinnin

both equally irregular both shot from theoretical devices so they start the contest at exactly the same velocity, I thinks it be a good question

Discussion about conicals is irrelevant to this debate.

Given equal velocity betwixt smoothbore and rifled bores at the muzzle (all else being equal), the answer to the hypothetical question can be found via any online ballistic calculator. Methinks the question is moot. There is no magic imparted on the spinning ball that reduces drag and promotes higher velocity. Simple truth of the matter is that the spin of a round ball is nested in the boundary layer and thus does not interact with overall drag components.

The general consensus here is that smoothbore balls rotate randomly and are thus influenced by imperfections of form and construction as you point out. Quantify the spin they generate please, and explain why it does not contribute to higher retained velocity as well. Sorry, but KH's assumption/conclusion/question is simply unsupported by physics, new or old.

Tell me please, what is the gyroscopic stability factor(Sg)of a roundball at 1800 fps, 1300 fps and 900 fps? Pick a caliber of your choice, use pure lead density in applicable calculations.

Because I am fairly benevolent I'd like to tell you not to waste your time trying to figure that out. Round balls have center of pressure(cp) and center of gravity(cg) co-located, therefore there is no moment arm to consider in calculation. Does the spin of a RB impart gyroscopic stability? Yes. Does in mean anything insofar as drag is concerned? No. A sphere presents the same drag form regardless of orientation to path. When the axis of rotation is other than parallel to path the magnus effect influences that path via aerodynamic force. The amount of that force is very small and will not significantly affect the distance the ball travels unless the deviation is downward.

 

[Stumpkiller]

Where does the energy go?

Into esotaric trivial theoretical discussions?

Now, if you were to roughen the top of the smoothbore barrel's bore so the ball has a backspin it should generate lift and go farther than an axial rotating ball. :rotf:

At least it may work for those who shoot on paper instead of at paper. :yakyak:

 

[John Wasmuth]

It actually boils down to how much finkilium is used in the thrust capasitator.

 

[Stumpkiller]

I figured it was something like that. I started to make a post about the scalar moment of inertia and the vector angular velocity in regards to the angular momentum . . . and the ghost of Daniel Boone gave me a head slap and told me to go to bed and get some sleep so I can go hunting in the morning. The deer ain't got no slide rules, don't give no points for theory and a hole in their vitals is all they stop for.

 

[John Wasmuth]

Good idea.

 

[Dphar]

I could almost agree with you if black powder burned progressively if the powder choosen properly meaning the fast powders with lighter ball and the slower powders with the heavy ball there would not be that much unburnt powder on the ground. OK back to speed vs rifling since blackpowder does not burn progressively the black powder doesn't build pressure as does modern powders it only has so much push and when the black powder burns out in the barrel there is no increase in pressure. With black powder upon ignition as the ball travels down the barrel the pressure will go down because of the pressure chamber ( the barrel) increases and the inside pressure (Expanding gases) begin to take up the area made behind the ball then pressure begins to fall and because it has burnt the powder there is no increase in speed you can't apply modern powders physics to black powder is doesn't work the exactly same way All things being equal the smooth bore should have a higher muzzle velocity

Do you actually know how BP burns in a barrel? So far as I know there are no modern studies on this at all. Period. From what has been done and ballistic studies BP has the characteristics of a fast burning powder and a slow burning powder.
A 45 colt revolver with a 7.5" barrel will make about 1000 fps with BP if old higher capacity cases are used. I had a 4 3/4" barreled 38-40 that would make 980+ with BP and a 180 gr lead bullet using 35-37 gr of fff. Yet the same powder will not "burn out" in a long kentucky barrel and cause the velocity to fall off unless a very light charge is used.
The English at one time used to roughen the bores of shot guns from a few inches up from the breech since this increased penetration (the velocity was higher). But it caused other problems (harder to clean for one) and fell from use pretty quickly as I recall. But reading this and some experience I have had with poorly made rifle barrels indicates that rough bores make more velocity.
I think if you go to Lyman's book you will find that even relatively light charges will produce higher velocity in longer barrels. So the "powder burning out" does not mean there is no more work done.

I don't believe ANYONE has ever found "unburned powder on the ground". I suppose in theory its possible but I think that Brockway was pulling Ned Robert's leg in this. And do not believe these guys were not willing to do this. I am sure that Brockway thought that how he determined powder charges and such was none of Ned's business.
These guys did not give away secrets. There were people shooting for MAJOR sums of money in the late 19th century. Winning enough gold for example that is was necessary to pay a boy to help carry it to the train station.
So Pope, Warner or Brockway are not going to tell some gun writer anything they thought was their proprietary information.
Nor were these guys above cheating to win. Such as shooting scratch rifled barrels in smooth bore turkey matches.
Barrel makers STILL don't give out secrets. They take too much work to learn.

Dan

 

[TKelly]

Hey there Just J!

I have a correction here:

A spinning round ball with linear velocity will create reduce pressure in the direction of spin and therefore, veer off into that dierction. This phenomenon is called the Magnus effect. In doing so, it will curve from linearity and in effect, decrease its distance.

* A rifled round ball would have exhibited these rotational effects as well upon the round bal, due to intended imparted spin. That's why the rifle worked best on the conical, a less spherical projectile, whose gyroscopic effects tended to stabilize its trajectory. PS.

I was thinking of the rifled conical when I anwered your question, previously. Sorry

 

[TKelly]

Hey there Josh!

I've concluded that a round ball with spin will tend to curve into that direction via the magnus effect. However, the less spherical a projectile is, when shot from a rifle, the more gyroscopic effects it will become more prominent to counteract the magnus effect.

This is the reason that the conical projectile was so successful. It obturated along the length of the barrel, allowing gaseous pressures to build up a greater force within the barrel, causing a greater force to push the conical into its trajectory. We therefore, have reason to expect a greater muzzle velocity as well as more spin.

PS.

Since the round ball launched from a smooth bore lacked spin, it was primarily a victim of deflection and the "knuckle ball syndrome".

 

[TKelly]

However, the percussion round ball has greater linear velocity (for some reason) and therefore, is more able to traverse more ground along the horizontal within the same time period.

I thought we were assuming the same KE for both, and both are .58 caliber.

By definition of a lead round ball with the same kinetic energy, both would have to weigh the same and have the same velocity.

So given the same velocity, same caliber, same weight, the only variable remaining is the gyroscopic action.

I'm assuming this is a purely hypothetical question as I would not expect the difference in range to be as great as you state.

Josh

You are exactly correct here Josh!

I overlooked the possibility of deflection. I prematurely attributed the shortness in range to the internal physical dynamics of the smoothbore muzzleloader and its lack of efficiency.
I envisioned gases being lost due to an improper sealing between the round ball and barrel, as opposed to the conical and barrel.

 

[Danbo]

KH, a suggestion for you:

"Modern Exterior Ballistics" by Robert McCoy

"Understanding Firearms Ballistics" by Robert Rinker

 

[TKelly]

Hey there Stumpkiller!

Yes! I agree, there should not be an increase in velocity here in this instance.

However, if a conical where to be the projectile, I would expect greater efficiency in the conversion of KE to translational energy due to obturation of the conical. This would allow for greater pressure build up within the barrel and subsequently, a greater propulsive force. A higher velocity would then be observed.

 

[TKelly]

Hey there Robtattoo!

The only problem here is that we're dealing with round balls here.

Conicals obturate to a much greater degree than do round balls.

So, both muzzleloaders end up having the same KE and the same muzzle velocities.

The smoothbore round ball get's seriously deflected. That's the only logical reason for its short range.

 

[TKelly]

Hey there Colonialist!

Yes! You are correct in everything you've stated here, with the exception of one thing.

*Provided that you've correctly measured your powder(either by weight or by volume), it will provide an equivalent amount of Kinetic Energy.

 

[TKelly]

I didn't know at the time that round balls don't obturate. Well not to any appreciable degree anyhow.

Sorry!

I remember this part being fun when I though that I was on to something...

 

[TKelly]

I was initially thinking along those lines, as well. However, round balls don't obturate and create that much more pressure buil-up, to manifest that much velocity.