Round Balls in smooth Bores

[GregLaRoche]

I am trying to understand obturation in smooth bores. What does it do? Supposedly the ball deforms to fill any ball and bore apace, keeping the most pressure behind the ball. That’s a reason for the ball being pure lead soft.

This makes sense as the ball travels down the bore and should be meeting it’s maximum velocity, at the muzzle. As I understand, the perfectly round ball should be the most aerodynamic and therefore the most accurate.

When the ball obturates, it is no longer the once perfectly aerodynamic sphere. It has the propensity to wobble and spin in an non concentric flight.

With a smooth bore gun. Wouldn’t it be better to use a ball of harder alloy, so it does not obturate and retains its perfect aerodynamic form? With wad and patches being used to make the seal between ball and bore?

 

[Erwan]

Normally when shooting with smooth bore this is always with the biggest ball (pure lead or not) and the cotton patch thickest for the bore the bullet must be as tight as possible and the powder load relatively consequent, in this way the bullet keeps a good precision ..... as in a smooth barrel nevertheless but good if the speed and the pressure are quite high.

 

[smo]

Or you can shoot them without a patch, my bore mice .653, and I shoot a 648-.642 ball.

Bare ball held in the bore by your choice of wad/ card.

 

[Stumpkiller]

I use 0.648" round balls in my 0.662" bore. Most commonly with 2-1/2 turns of paper formed into rolled cartridges.

It shoots as well with 0.010" (thin) cloth patching. I really can't say if the balls obturate at all in the bore at the velocities and pressures I shoot.

 

[hawkeye2]

It's my opinion and experience that a round ball does not obturate at all in a smoothbore. It merely bounces or rattles down the barrel and exits whatever direction as a result of its last bounce. The closer to bore diameter the better the accuracy. This applies to a naked ball, patching or wads change things big time. A round ball isn't aerodynamic, a boattail spitzer bullet is. A perfectly round ball would of course be more aerodynamic than a misshaped or deformed one. Smoothbores digest most any kind of lead as long as care is taken not to deform the ball when loading. Hard lead works very well and a smoothbore is a good vehicle to use up your supply of reclaimed range lead.

 

[Britsmoothy]

Obturation is only very slight but increases with greater mass of a pure lead ball. It is also very influenced by the charge propelling the ball.
In other words a ball is not misshaped by much at all.
I have seen extreme cases using breach loaders and cartridges but if obturation happens to a great amount in a muzzleloader the ball resembles the re entry vehicle used by the appolo space programs. This is however rare in most muzzleloaders due to the gentle nature of black powder.

 

[dave951]

The minor amount of obturation in a smoothbore is negligible in regards to accuracy. The round ball isn't very aerodynamic.

 

[Many Klatch]

Greg, I believe you are overthinking it. It's a 60 yard gun, any accuracy beyond that is a temporary gift from the Gods. Shoot and enjoy. I shoot my smoothbores with a .010 spit patch. The patch/ball combination is loose enough that I don't need a short starter. I can usually get off 30 shots without having to clean. The only obturation that might come into play is having to beat a tight fitting lead ball down the bore.

 

[George]

Greg, I believe you are overthinking it. It's a 60 yard gun, any accuracy beyond that is a temporary gift from the Gods.

I think we sell the guns and ourselves short if we just accept that as a fact. I have not found it to be true, and I think if more people actually tried shooting at longer distances they would be pleasantly surprised.

Spence

 

[GregLaRoche]

I’m only interested in fifty yard targets. And for now I am using a spit patch with semolina. The better shooters at my club use this combination so that’s what I’m going with for now. They do say they only use pure lead.
What I have gotten from this post is it doesn’t matter if I use a harder lead. That’s good news for me, because most of my lead is range scrap from a 25yard indoor range, where most shoot handguns. Jacketed bullets are not allowed and the lead used tends to be on the hard side. Pure lead is much harder for me to come by.

 

[hawkeye2]

I have heard from a few that hard lead shoots better than soft because it is more difficult to deform and it doesn't suffer any damage as it rattles down the bore. Not sure if that's true or not as all I've shot was soft. If you have a source of marbles that are close to bore diameter they will work too for practice.

 

[smo]

I have heard from a few that hard lead shoots better than soft because it is more difficult to deform and it doesn't suffer any damage as it rattles down the bore. Not sure if that's true or not as all I've shot was soft. If you have a source of marbles that are close to bore diameter they will work too for practice.

Roundball, did the marble shooting on here a few years back.

He found a source for specific size glass Marbles from overseas somewhere.... said they shot fine.

Seems as if he played around with brass balls as well...

 

[hanshi]

The .600" prb goes about 3" or less at 50 yards for 3 shots. Don't underestimate smoothbores.

 

[smo]

The nut behind the butt....has a lot of influence on the projectiles destination.

 

[George]

The .600" prb goes about 3" or less at 50 yards for 3 shots. Don't underestimate smoothbores.

I don't shoot at long distances, but I've spent a couple of sessions over the years just trying to see what the guns are capable of, and whether the accepted dogma that roundballs from smoothbores always head for the moon beyond 50-60 yards. I convinced myself they don't.

Standard NMLRA 100 yard target at 75 yards, 1997, 3.5" group:

Homemade 6" bull at 100 yards on a very windy day, 2014, <4" group:

Both sessions with the same 46" 20 gauge flintlock smoothbore with no rear sight. Not exactly bench rest, but my version, which is a small sandbag on top of a cardboard box on the hood of my Jeep, with me standing and draped.

As hansi said, don't underestimate the smoothbores.

Spence

 

[ord sgt]

I shot smoothbore matches in the N-SSA. They didn't allow patch material to be used, as it was a fire hazard. I was using a .69 caliber musket, shooting a .678 home made roundball. I took two farrier's rasps and roughed up the roundball. Accuracy was good at 25 and 50 yards. Also tried wrapping the lead roundball with aluminum foil and dipping them in a mixture of Crisco and beeswax. My .02 cents.

 

[Griz44Mag]

I have heard from a few that hard lead shoots better than soft because it is more difficult to deform and it doesn't suffer any damage as it rattles down the bore. Not sure if that's true or not as all I've shot was soft. If you have a source of marbles that are close to bore diameter they will work too for practice.

I hunted with a guy who told this tale, - he discovered after making a very long trip to hunt that he had no roundballs. A local search turned up nothing.
A trip to the local variety store produced a bag of marbles very close to bore size.
He killed a very nice elk cow at about 70 yards with a double patched marble. The marble was recovered intact.
No round ball is going to be deformed or damaged being shot from a black powder gun. It is very likely it will get damaged being loaded with a very tight fit and a hard pounding to start and\or set the ball to the powder. It will also likely be damaged when it impacts the final destination.

 

[George]

A trip to the local variety store produced a bag of marbles very close to bore size.
He killed a very nice elk cow at about 70 yards with a double patched marble.

It's HC/PC.

THE VIRGINIA GAZETTE
September 22, 1774
LONDON, July 11July 13. We hear from Haltwistle, that on Thursday last, a Collection of wild Beasts being in a Barn, a large Russian Bear broke loose, and instantly devoured two of the other Animals of the Collection; then made an Attempt upon one of the Keepers, who narrowly escaped with his Life. Upon this Alarm, the whole Town assembled together around the Barn, and fired several Times at the Beast, but to little Purpose, as they could not readily procure Balls, but at last a young Gentleman shot it dead with a small Marble.

Spence

 

[Griz44Mag]

It's HC/PC.

THE VIRGINIA GAZETTE
September 22, 1774
LONDON, July 11July 13. We hear from Haltwistle, that on Thursday last, a Collection of wild Beasts being in a Barn, a large Russian Bear broke loose, and instantly devoured two of the other Animals of the Collection; then made an Attempt upon one of the Keepers, who narrowly escaped with his Life. Upon this Alarm, the whole Town assembled together around the Barn, and fired several Times at the Beast, but to little Purpose, as they could not readily procure Balls, but at last a young Gentleman shot it dead with a small Marble.

Spence

I did not know they had marbles back then. Pretty cool - from 247 years ago!
Just one curiosity - why the heck did someone bring a bear all the way from Russia?

 

[George]

Just one curiosity - why the heck did someone bring a bear all the way from Russia?

Since other wild animals were mentioned, I would assume a circus, traveling animal show, or some such.

Marbles were apparently commonly available.

The Pennsylvania Gazette
January 5, 1748
From the GENERAL MAGAZINE. A New Method of making BULLET MOULDS.

THE Badness of the Bullet Moulds brought into America for common Sale, and the Difficulty of meeting with one of them, bad as they are, that will fit one's Gun , will render the following Invention, for making (easily) true and exact Bullet Moulds, agreeable to all Lovers of good Shooting. First provide yourself with two Pieces of Lead about an Inch and Half, or two Inches Square, and half as thick, and smooth their Faces, so that when joined they may make near a Cube; then get some Marbles (such as Boys play with) from the smallest to the Size that fits your Gun, oyl or grease the Marbles and Lead well; and with the Assistance of a Smith's Vyce, with two flat Pieces of Iron in the Chaps of it, press the two Pieces of Lead with the smallest Marble between, till the Marble be quite sank in the Lead; then put in the next greater, always remembering to keep the Lead and Marbles well oyl'd do thus successively, till you have brought it to the Size you want: And, to prevent the Bullets having Edges, smooth the Faces of the Mould, and press in the same Marbles several Times, by which Means you may make Moulds of wonderful Exactness. Then cut a Gate and fit the Corner with Pins, to keep the Pieces in a proper Position for casting. When you use it, smoke it well, and take Care the melted Lead be not so hot as to burn Paper.

Spence