very slow twist

[coloradoclyde]

A lead ball then....

 

[George]

A lead ball then....

A well know problem with muskets loaded without patches or wadding, as shown by Robins in the early 18th century. Called the Magnus effect, first described by Isaac Newton in the early 1670s. Discussed at length by Cleator in an Essay on Shooting, and the experiment proving that musket balls curved because of spin on some axis other than the longitudinal one is described in detail in Cornhill Magazine, 1899, at this link.
https://books.google.com/books?id=...Why of Long Shots and Straight Shots"&f=false

Spence

 

[coloradoclyde]

:applause: :applause:
Very good Spence....

If you give a thought to the projectile being fired, you have to ask yourself why any spin at all is necessary for a roundball. There's no question an elongated projectile needs spin to stabilize it, and the longer it is the more/faster spin it needs. That's easy to prove by shooting one with too little spin and watching it keyhole. But a round ball...? No matter which way you turn it, it's all the same. Can't keyhole, but what if it does, it's all the same.

Ever since I figured out that accuracy with a round ball in a smoothbore is not all that different from a rifle, I've suspected that we've been thinking about it sorta backwards. The way I load my smoothbore guarantees the ball doesn't spin, and with no spin whatsoever it will shoot sub-4" groups at 100 yards. So, what is the spin contributing to accuracy when that ball is shot from a rifle with spin? It can't be much.

I suspect that the situation is more like this...spin certainly increases accuracy with long bullets, but it's the case that spin of a round ball adds nothing to accuracy, it just doesn't take anything away from it. Round balls don't need spin at all, they just tolerate it. Doesn't help, doesn't harm.

Spence

Now you know that spin can have both a stabilizing affect or a destabilizing affect on a projectile dependent on other factors....

Think of rifling as a predictable spin that stabilizes the projectile...
Without rifling, the projectile is more susceptible to other forces (like drag) resulting in the magnus affect changing the flight path...


The questions I have are; Does a large ball generate more Magnus force than small ball?
And does forward velocity increase or decrease the affect?
If so, which would be more inherently accurate fired from a muzzleloader?

 

[George]

Without rifling, the projectile is more susceptible to other forces (like drag) resulting in the magnus affect changing the flight path...

Not so. Magnus force has nothing to do with the ballistics of the balls I'm firing. Spin around the flight axis prevents spin around any other with a rifled barrel, but so do the wads or patches used in a smoothbore. The comparison has to be between spin around the flight axis or no spin of any type around any axis at all.

The questions I have are; Does a large ball generate more Magnus force than small ball?
And does forward velocity increase or decrease the affect?
If so, which would be more inherently accurate fired from a muzzleloader?

Magnus force is a red herring in this problem.

So, my question is still the same as before.... is any spin necessary for a round ball to shoot accurately?

Spence

 

[Artificer]

The way I load my smoothbore guarantees the ball doesn't spin, and with no spin whatsoever it will shoot sub-4" groups at 100 yards. Spence

How have you determined there is no spin on the ball the way you load it?

Since a round ball is not perfectly round and not the same density all the way around - due to even a snipped/filed off sprue or air pockets or the fact the mold does not cast a perfect round ball, the ball is going to wobble in flight and that causes some kind of spin.

Gus

 

[George]

There's no way to know what the ball is doing in flight, as far a I know. It's all conjecture. My idea is that if it has significant external unevenness or internal differences in density, as with a void, it undergoes a reorientation. Any protuberances. such as the sprue, will be forced to the rear by the air stream, like a wind vane. If there are areas of different density, it will reorient itself around the center of gravity if that isn't in the center of the ball. That would be a momentary rotation or change of position, but would not generate spin. I know of no forces which would act to take it out of that new orientation once it is complete. I've never been able to understand why a ball would "wobble" in flight.

When I say my smoothbore ball has no spin, I mean to say it has no spin induced by rubbing against the side of the bore, so that it has zero spin when it exits the muzzle. That's true whether wadded or patched.

Spence

 

[coloradoclyde]

So, my question is still the same as before.... is any spin necessary for a round ball to shoot accurately?

Spence

Yes!...Because although you think your balls are not rotating, they will move more over distance and as you velocity drops off...
A rifled gun will shoot better than that 4" at 100 yards...
The necessity of rifling ultimately is dictated by how far and how accurate the shooter wants to shoot.

 

[coloradoclyde]

I know of no forces which would act to take it out of that new orientation once it is complete. I've never been able to understand why a ball would "wobble" in flight.

First the ball would have to re-stabilize, Which it doesn't because the time in flight is to short.

Secondly, you are fighting forces like crosswinds and transonic disruption that want to destabilize the ball further....

It's only possible to fire a seemingly motionless ball over a short distance and time...

Even if you fired the ball in the vacuum of outer space, you still have gravity as a force to contend with..

 

[George]

A rifled gun will shoot better than that 4" at 100 yards....

Of course it will. That 4" figure, however, is from a very old man with trifocals shooting a smoothbore with no rear sight. That same smoothbore and load shot by some hotshot young guy with eagle vision and a rear sight would do much better than that, I believe.

Spence

 

[George]

Well, Clyde, as a first impression, I'd say your conjecture is no better than my conjecture. A few more big words and a lot more magical thinking, of course, but generally speaking, just one man's opinion, as is mine. I like mine better, but then I would, wouldn't I. :haha:

Last time I checked there was what is called zero gravity in outer space. And, what does gravity have to do with the problem, any way? It's no more relevant than Magnus effect.

Spence

 

[coloradoclyde]

Last time I checked there was what is called zero gravity in outer space. And, what does gravity have to do with the problem, any way?

Zero gravity! :hmm: indeed!...Except that every object in space is moving in some manner and "stars" fall from the sky..... :hmm:

 

[George]

Oh, I see....and that destroys your accuracy? This stuff is a lot more complicated than I first thought.

Spence

 

[coloradoclyde]

If we keep questioning each others answers, will we ever arrive at a consensus?..... :haha:

 

[George]

No, but it's the thing to do, these days.

In the old days we called it the blind leading the blind.

Spence

 

[coloradoclyde]

Even a blind squirrel finds a nut every once in a while.... :haha:

 

[bender20]

In theory I believe that ball would "knuckle" when it reached a certain speed. I don't know why but I do know knuckleball pitchers need to be careful with the speed at which they throw if it is to fast or to slow it will not knuckle.

 

[George]

Ain't it the truth. I just found one.

Spence

 

[George]

The fastest knuckle ball is about 110 feet per second. The average smoothbore ball is probably in the 1200-1400 fps range. I don't believe a comparison between the two is logical.

I came to the conclusion a long time ago that the so-called knuckleball effect was probably more likely a knucklehead effect. :haha: :haha:

Spence

 

[coloradoclyde]

In theory I believe that ball would "knuckle" when it reached a certain speed. I don't know why but I do know knuckleball pitchers need to be careful with the speed at which they throw if it is to fast or to slow it will not knuckle.

:hmm: Like the transonic zone between supersonic and subsonic.....
In the case of the pitcher, velocity changes flight time...to fast and the ball reaches the batter before it can knuckle...To slow and it might foul or strike the pitcher...

 

[Loyalist Dave]

Uh, Dave,

You do realize the size targets used for the Baker were SMALLER than what you fired on at the 200 yard line on active duty? The 5 ring bullseye was 12" in diameter, the 4 ring was 24" (same width as the Baker target), the 3 ring was 36 inches and the 2 "ring" was the entire 6 foot by 4 foot target. Just because a target is big really doesn't mean much with good marksmanship and a good rifle.

I just can't get it out of my mind the British Shooter who recently fired his Original Baker rifle at 200, 300 and 400 yards OFFHAND and put the first shot into pretty much the center a man sized silhouette at each distance. He used an original mold, but I don't know if he used leather or cloth patches.

There were recorded kills with the Baker during combat, somewhat beyond 400 yards during the period as well, though most likely shot from some kind of a rest.

OK so?

You are talking about ONE rifle, with ONE shooter, in ONE event. You may in fact be talking about a person who would be a distinguished marksman with that weapon, and proclaiming that the majority of the shooters would do as well.

The British Standard said that at 300 yards if you put all of the ball 3" above the ground into the target, that was the same as hitting the center of the target. If it was common place to do much better, then they would have had different standards.


There were recorded kills with American Long Rifles at 400 yards. (iirc) There is one at that range with a bess. Jacob Deverbaugh fired at 100 yards at a barrel head, 100 times [standing], and did not miss. This was recorded by Daniel Morgan in the 1760's. He picked his best shooter..., not his average shooter.

LD