Round ball spin.

[mjpchief]

During our discussion on this subject at the coffee shop we figured that the only way to get the hollow point in the center of the ball would be to drill the hole after the ball had been short started. Done figured how to do this and have the tool to do just that. Of course we haven’t loaded and fired one of these projectiles yet but wouldn’t put it past us to at least try it. All the while knowing that we are wasting our time on this project but this bunch of old farts need something to take up our time and keep us out from under our wives feet. We have seen a lot of good answers to this endeavor and enjoy reading them but at the same time as said before we realize we are peeing up a rope here.

 

[le125verne]

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.

Round ball "keyhole"?

 

[windini]

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

Drill the hole all the way through!

Note to @mjpchief : I personally would not form cavities in round ball, but I support to the death your right to discuss it over coffee! Or even other beverages!

 

[necchi]

I can't speak to rifles from lack of actual experience,

Of course your right about the revolvers, but the short barreled and different twist rates of the revolvers and pistols are a complete different game then that of a rifle, thus the distance and respective accuracy of the different weapons.

Further, the ball engages the rifling during its passage through the barrel and that deforms it.

In a proper fitting(and accurate) "patched round ball", it's the fabric of the patch that engages the rifling, the patch holds the round ball snugly in position and will "impart" it's pattern to the ball. It's a tricky combination of proper patch thickness and lube properties that the real top shooters seek to be smacking that X-ring on a regular basis. Guy's are hitting that X-ring 5 out of 5 at 100yrds

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.

Yup, it's "areodynamics" and "ballistics", and all that lead folks to the development of the bullet centuries ago,, an elongated projectile, a different spin rate,,
There's even arguments about round ball "Obduration" caused by the explosive charge behind it in the barrel.
Your thinking, that's a good thing,, keep an open mind, there's ton's of stuff to learn,,

 

[Tumbledown]

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!!!

Patched round balls in long guns do not flatten when fired.

 

[64Springer]

Round ball "keyhole"?

At no time did I say round balls keyhole.

I said some projectiles keyhole.

Some projectiles include bullets.

Bullets keyhole.

 

[Mogadishu Meanderer]

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

Easy…..keep round!!!

 

[Mogadishu Meanderer]

Patched round balls in long guns do not flatten when fired.

Yes sir, they do not flatten but they don’t remain perfectly round either. As my post indicated I was referring to revolving pistols where I have had the opportunity to recover lots of “round” balls! I believe that let’s say, a patched stainless steel balls would probably remain a round at ML velocities in a long gun since it harder but if you push it fast enough it will cease being perfectly round as well. I believe Physics has some to do with it, I am not a rocket scientist but I did stay at the Holiday Inn last night! Let me see if I can figure out, again, how to post a pic!

 

[stikshooter]

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.

The ball does (NOT) contact rifling ,the patch does that job and pure is best for balls especially . Less velocity /short barrel needs all the help it can get using pure for expansion .

 

[Tumbledown]

Yes sir, they do not flatten but they don’t remain perfectly round either. As my post indicated I was referring to revolving pistols where I have had the opportunity to recover lots of “round” balls! I believe that let’s say, a patched stainless steel balls would probably remain a round at ML velocities in a long gun since it harder but if you push it fast enough it will cease being perfectly round as well. I believe Physics has some to do with it, I am not a rocket scientist but I did stay at the Holiday Inn last night! Let me see if I can figure out, again, how to post a pic!

Your post I referenced indicated round balls flatten into tic-tac shapes regardless of the gun, unless you're aware of some kind of flintlock revolver.

I have recovered PRBs from the berm. They do not deform.

 

[oldwood]

Punching needless holes in round balls , would be a waste of time and effort. Probably not too entertaining as well.

 

[ibud38]

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.

I agree, a soft lead ball will obturate upon fireing the charge creating a wide driving band to engage the rifleing providing the twist rat is not to fast, eg.1:60.

 

[Dude]

How would you know if it keyholed?

 

[Rifleman1776]

How would you know if it keyholed?

On paper the hole would not be round. Otherwise the shot could be wildly inaccurate.

 

[mjpchief]

Punching needless holes in round balls , would be a waste of time and effort. Probably not too entertaining as well.

We are pretty easily entertained. We are all retired and usually looking for something to do that we haven’t tried yet. We haven’t tried this yet but if people keep telling us we shouldn’t do we are going to end up doing it just because.

 

[GeronPG]

As someone mentioned, the soft round ball expands when it hits tissue anyway, which is what I assume you would hope to accomplish with a hollow point. So, in my opinion, the effort it would take to drill a hollow point into a lead ball, and the uncertainty about how it would affect the accuracy, together make it not worth the effort. It does, however, make a good conversation over a cup of coffee. And begs question: if you drilled a hollow point into a lead ball, how may angels could fit inside....?

 

[wiscoaster]

The ball does (NOT) contact rifling ,the patch does that job and pure is best for balls especially . Less velocity /short barrel needs all the help it can get using pure for expansion .

Well, OK, for rifles I'll agree, but not for revolvers.

 

[wiscoaster]

How would you know if it keyholed?

Exactly. Round balls don't keyhole. But their trajectory, and therefore accuracy is affected.

 

[wiscoaster]

On paper the hole would not be round. Otherwise the shot could be wildly inaccurate.

I haven't seen a single round ball make a perfect round hole yet on any of my targets.

 

[CZMark]

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.

If you do any serious study of ballistics, you'll find that while rotational velocity does indeed slow, it does so at an exponentially lower rate than forward velocity. A ball that has lost almost all of its forward momentum is still spinning at a fairly high rate.