Round ball spin.

[mjpchief]

Question this morning at the coffee shop about round ball spin. Does a round ball out of a rifled barrel spin on one axis only or will it “tumble”? Reason for asking is we are discussing putting a hollow point type of hole in a round ball. I know this is probably a worthless idea but it is a coffee shop discussion. Fire away.

 

[ppb]

Where is this coffee shop?
They must serve on hellofacup of coffee...

 

[64Springer]

All that hole will do is cause instability/wobble due to more weight on one side of the ball.

The rifling is designed to prevent tumble. So yes, it spins on an axis.

Doesn't always work though, and why some shooters experience "Keyholing" with some projectiles.

Bullet Weight/Bullet Speed/Twist Rate refuse to work in harmony.

 

[Sun City]

Most folks generally bring smokeless powder thinking into the BLACKPOWDER world and basically it just doesn't apply.

 

[springfield art]

Question this morning at the coffee shop about round ball spin. Does a round ball out of a rifled barrel spin on one axis only or will it “tumble”? Reason for asking is we are discussing putting a hollow point type of hole in a round ball. I know this is probably a worthless idea but it is a coffee shop discussion. Fire away.

Eh! Wouldn't bother!

 

[mjpchief]

Eh! Wouldn't bother!

Probably won’t but we needed something to discuss this morning

 

[mjpchief]

Where is this coffee shop?
They must serve on hellofacup of coffee...

Just straight black coffee. Honest.

 

[mjpchief]

Most folks generally bring smokeless powder thinking into the BLACKPOWDER world and basically it just doesn't apply.

No discussion of smokeless powder here.

 

[#BPBReloadingFFL]

Wobble ,Kind of like pumping ground water out of the earth.

 

[stikshooter]

Question this morning at the coffee shop about round ball spin. Does a round ball out of a rifled barrel spin on one axis only or will it “tumble”? Reason for asking is we are discussing putting a hollow point type of hole in a round ball. I know this is probably a worthless idea but it is a coffee shop discussion. Fire away.

Your right (worthless) cause what ever you do to unbalance the ball will be ugly ! I even weight balls in case there's a void/or contamination in the pure lead .; A habit from target shooting conicals as well as round ball , sameness of condition of bore/powder and your projectile is extremely important with BP especially !!/Ed

 

[springfield art]

Sometimes BP shooters are like those who try to improve upon the Mousetrap; it usually can't be done!

 

[Bnewberry]

Spin is on the axis…or should be. I wouldn’t think a pure lead round ball would need a hollow to expand at reasonable shot distances.

 

[Rifleman1776]

Spin is on the axis…or should be. I wouldn’t think a pure lead round ball would need a hollow to expand at reasonable shot distances.

Soft lead round balls do expand well. A deer shot .45 cal. ball becomes about the size of a quarter. As for the hole, nothing would be gained and on loading that hole would have to be exactly, perzactly, very precisely centered to not cause the ball to wobble. Not a practical idea at all.

 

[wiscoaster]

A lead ball bullet isn't a perfect sphere, especially not after getting squished with a ramrod or loading lever, so I'd expect it would start tumbling somewhere along its trajectory, given a long enough flight path.

 

[Loyalist Dave]

Question this morning at the coffee shop about round ball spin. Does a round ball out of a rifled barrel spin on one axis only or will it “tumble”?

Although soft lead, the force applied when loading is not enough to disturb the shape of the sphere, and neither is the firing going to obturate the ball, because the spherical shape of the portion of the ball prevents this. A flat surface on a conical is the opposite of a spherical shape, and promotes obturation of the base of the bullet.

The round balls for this type of rifle should be case from pure lead – not hardened, then the sprue cut should be smoothed or round with a small file or pocket knife, if the best accuracy is desired. I have heard of old riflemen, years ago, say that it mattered not whether the sprue surface of the ball is placed at the bottom or the top when loading the round ball rifle, but this is not reasonable and does not agree with my experience and that of the majority of experienced riflemen who use the muzzle-loading rifles. All experienced riflemen who use the modern high power rifles, as well as the most expert marksmen with the target or schuetzen breech-loading single shot rifles, know that the base of the bullet which rests against the powder and is first acted upon by the powder gas must be as perfect as possible and each bullet have the same shape of base, in order to give good, uniform accuracy. Of course, these same conditions obtain in rifles using the round ball; therefore, as almost no two cast round balls have exactly the same shape at the point where the sprue was cut off …,

…, Experienced experts agree that better accuracy with the round ball rifles will be secured by always loading the sprue surface of the ball at the top, or towards the muzzle.

…, Do not ram, or pound, the ball down the bore, and do not “whang” the ball with the ramrod onto the powder—simply seat the ball firmly on the powder with a light pressure on the ramrod. …, ramming or pounding the ball down the bore will upset it making it merely a slug of lead instead of a sphere and thus destroy all accuracy.

Ned H. Roberts 1866-1948 Developer of the modern, .257 Roberts cartridge and Author of The Muzzle-Loading Cap Lock Rifle c 1940

LD

 

[tenngun]

Howsomever in 2014 I was at the Midwest mud-de-vous in Leslie Arkansas. We had a teenage kid there that was shooting. It’s rare for me to shoot at an event. But I shot at this one.
This kid, I didn’t get his name, pounded the dropping’s out of his ball, I never saw anyone pound a ball so hard, and never missed

 

[wiscoaster]

Although soft lead, the force applied when loading is not enough to disturb the shape of the sphere, ....

Sorry, I beg to differ, even being an ignorant BP noob, because when I load a ball into a revolver's chamber it shaves a ring of lead off the ball. Maybe it's not exactly "squished" as I said, it's still definitely deformed by the act of loading. I can't speak to rifles from lack of actual experience, but given the force required to ram a patched ball down the bore of my Kentucky pistol, I can't hardly believe it remains a perfect sphere either.

Further, the ball engages the rifling during its passage through the barrel and that deforms it. Any little irregularity on a sphere's surface is going to disrupt the airflow around it. The ball's spin counteracts the disruptive force of the disturbed airflow, of course, but the spin rotational speed diminishes with time in the air.

 

[Tumbledown]

All that hole will do is cause instability/wobble due to more weight on one side of the ball.

The rifling is designed to prevent tumble. So yes, it spins on an axis.

Doesn't always work though, and why some shooters experience "Keyholing" with some projectiles.

Bullet Weight/Bullet Speed/Twist Rate refuse to work in harmony.

Actually, they DO work in harmony, when properly balanced. Change in one of those variables causes instability.

 

[Mogadishu Meanderer]

Sorry, I beg to differ, even being an ignorant BP noob, because when I load a ball into a revolver's chamber it shaves a ring of lead off the ball. Maybe it's not exactly "squished" as I said, it's still definitely deformed by the act of loading. I can't speak to rifles from lack of actual experience, but given the force required to ram a patched ball down the bore of my Kentucky pistol, I can't hardly believe it remains a perfect sphere either.

Further, the ball engages the rifling during its passage through the barrel and that deforms it. Any little irregularity on a sphere's surface is going to disrupt the airflow around it. The ball's spin counteracts the disruptive force of the disturbed airflow, of course, but the spin rotational speed diminishes with time in the air.

You are mostly correct sir. Lots of people continue to believe that the ball continues to be a sphere after firing when in fact is more like a tic tac. Folk worry about deformation while loading because you want the projectile as perfect as possible of course, but once the flint scrapes or the cap goes off is a whole different story. In some pistols with tight rifling in relation to chamber diameters the bearing surface of a round ball is up to an 1/8 of an inch and the ball ends up pretty elongated. I am not stating this because it sounds right, I have done lots of projectile recovery in soft medium to analyze them. I will not spend a minute of my life putting a hollow cavity in a RB but if I decided to do it I will test it out as scientifically as possible instead of speculating about it. I would do that while enjoying a cup of coffee of course!!!

 

[ord sgt]

Doesn't always work though, and why some shooters experience "Keyholing" with some projectiles.

I have always wondered.....how do you prevent a roundball from key holing?