Motion of Patched Round Ball in Flight

[GregLaROCHE]

What happens to a patched round ball when it leaves the muzzle of a smooth bore. Does it start to spin on one of its axises. Wobble some, or just stay in the same orientation as it was loaded. I’ve heard and read a lot of different things and would like to know what members here think.

Thanks

[seetrout]

I have no idea. Surely someone somewhere has slow mo video to find out. You Tube it!

[sharps4590]

Hmmm...never thought about it. Be interesting to see what turns up

[mooman76]

I would think it would spin some, not allot but spin different every time according to how the wind catches it. Just a thought.

[GregLaROCHE]

I read somewhere that a bare ball, rolls down tte bore and develops a spin, making it more accurate. I can’t believe it is more accurate, or a lot more competition shooters would be doing it.

[pietro]

.

Since the round ball is a tight fit, with the patch engaging the rifling, it will rotate according to the barrel's twist rate, just like a conical.

Whether or not a PRB will be stabilized will depend on the rate of the barrel's rifling twist; which is why a slow twist (like 1:60") is considered best for PRB's & a fast twist (like 1:28") is better for conicals.

A compromise twist (like 1:48") is just that, a compromise that will work with both PRB's & conicals - but not as good for either with the proper twist rate.

.

.

[Edward]

I read somewhere that a bare ball, rolls down tte bore and develops a spin, making it more accurate. I can’t believe it is more accurate, or a lot more competition shooters would be doing it.

A tite patched ball should always be more accurate as it will be more consistent (velocity wise ) shot to shot and we all know doing every thing the same eliminates variables there fore you go home with the turkey

[mooman76]

Smooth bore

[longbow]

I haven't shot round ball, patched or naked, from smoothbore musket but I have shot round balls from a Pedersoli 12 ga. side by shotcup. These were naked 0.690" round balls sitting on top of hard card and/or felt wads. Accuracy was non existent! Balls hit randomly around targets at even 25 yards. All you have to do is look up some of the info on smoothbore military muskets using loose round balls and you will find out how poor the accuracy was. 50 yards was generally considered the maximum range that a naked round ball (military loading) could be depended on to hit a man size object.

The old military muskets were loaded with round balls considerably under bore diameter to allow "windage" and easy/fast loading in fouled bores. Precise accuracy was not expected as smoothbore musket fire was generally used as volley fire.

A bit of reading material:

https://bowvsmusket.com/2015/03/01/m...y-at-80-yards/
https://scholarworks.iu.edu/journals...d/19841/25918/

There are a number of smoothbore musket shooters that report quite good accuracy to 70 yards or more using patched round ball and I have read of smoothbore shooters using patched round balls winning blackpowder matches against rifle shooters out to 100 yards.

I have shot lots of round balls from a modern 12 ga. shotgun with varying results. A loose fitting round ball can obviously bounce down the bore and can easily roll so picking up random spins from the bore friction on one side. With loose round balls accuracy was about the same as with the muzzleloading shotgun... essentially non-existent. However, with a round ball somewhat larger than bore size or and undersize RB in a shotcup with good fit, accuracy to at least 50 yards can be very good as in 3" to 4" groups. Much beyond 50 yards in my experience groups start to open up quite quickly and by 100 yards groups are undependable and ranging from 8" to 12". While this is opinion, I think it is common opinion in that the round ball, even launched with no spin at all, seems to pick up random spins from air drag so that groups become exponentially larger at longer range due to the "knuckle ball" effect of random spins which I have seen referred to as "trombone" trajectories.

So, the short story is, in my opinion anyway, that your patched round ball shot from smoothbore should provide good accuracy to at least 50 yards, reasonable (hunting level) accuracy to 70 yards or even further but groups will start to open up and get larger quickly with with increased range due to random spin of the ball induced by air drag on little imperfections.

Probably more words than you wanted. Oh well, I talk too much!

All my opinion only.

Longbow

[indian joe]

.

Since the round ball is a tight fit, with the patch engaging the rifling, it will rotate according to the barrel's twist rate, just like a conical.

Whether or not a PRB will be stabilized will depend on the rate of the barrel's rifling twist; which is why a slow twist (like 1:60") is considered best for PRB's & a fast twist (like 1:28") is better for conicals.

A compromise twist (like 1:48") is just that, a compromise that will work with both PRB's & conicals - but not as good for either with the proper twist rate.

.

.

He did say smooth bore in the original question...........................

[GregLaROCHE]

.

Since the round ball is a tight fit, with the patch engaging the rifling, it will rotate according to the barrel's twist rate, just like a conical.

Whether or not a PRB will be stabilized will depend on the rate of the barrel's rifling twist; which is why a slow twist (like 1:60") is considered best for PRB's & a fast twist (like 1:28") is better for conicals.

A compromise twist (like 1:48") is just that, a compromise that will work with both PRB's & conicals - but not as good for either with the proper twist rate.

.

.

I am asking about smooth bore. Rifled bore is another subject.

[indian joe]

I haven't shot round ball, patched or naked, from smoothbore musket but I have shot round balls from a Pedersoli 12 ga. side by shotcup. These were naked 0.690" round balls sitting on top of hard card and/or felt wads. Accuracy was non existent! Balls hit randomly around targets at even 25 yards. All you have to do is look up some of the info on smoothbore military muskets using loose round balls and you will find out how poor the accuracy was. 50 yards was generally considered the maximum range that a naked round ball (military loading) could be depended on to hit a man size object.

The old military muskets were loaded with round balls considerably under bore diameter to allow "windage" and easy/fast loading in fouled bores. Precise accuracy was not expected as smoothbore musket fire was generally used as volley fire.

A bit of reading material:

https://bowvsmusket.com/2015/03/01/m...y-at-80-yards/
https://scholarworks.iu.edu/journals...d/19841/25918/

There are a number of smoothbore musket shooters that report quite good accuracy to 70 yards or more using patched round ball and I have read of smoothbore shooters using patched round balls winning blackpowder matches against rifle shooters out to 100 yards.

I have shot lots of round balls from a modern 12 ga. shotgun with varying results. A loose fitting round ball can obviously bounce down the bore and can easily roll so picking up random spins from the bore friction on one side. With loose round balls accuracy was about the same as with the muzzleloading shotgun... essentially non-existent. However, with a round ball somewhat larger than bore size or and undersize RB in a shotcup with good fit, accuracy to at least 50 yards can be very good as in 3" to 4" groups. Much beyond 50 yards in my experience groups start to open up quite quickly and by 100 yards groups are undependable and ranging from 8" to 12". While this is opinion, I think it is common opinion in that the round ball, even launched with no spin at all, seems to pick up random spins from air drag so that groups become exponentially larger at longer range due to the "knuckle ball" effect of random spins which I have seen referred to as "trombone" trajectories.

So, the short story is, in my opinion anyway, that your patched round ball shot from smoothbore should provide good accuracy to at least 50 yards, reasonable (hunting level) accuracy to 70 yards or even further but groups will start to open up and get larger quickly with with increased range due to random spin of the ball induced by air drag on little imperfections.

Probably more words than you wanted. Oh well, I talk too much!

All my opinion only.

Longbow

Longbow
Fit to the bore eh!
Many moons ago - We had read some about this stuff but had no clue what we were doing - bought a clunker belgian shotgun with a blown right side barrel - we cut it ! ....well the choke was already gone so why leave all that useless barrel on there ? 16 inches was legal at the time so we did 16 and one quarter inch (just in case we encountered a cop with a shrunken tape measure) - cut the forend and lopped the butt to bring it all into proportion ....next was a yard sale purchase of some assorted junk and found an olde fashioned ball mold in the bottom of the box - 16 gauge - cast some of those for fun - now what ? maybe we can shootem outta the sawnoff ? First loading attempt was a no go - the 16 gauge ball was all rattly in the poly wad
so having read some about Danl Boone and Davey Crocket and those old muzzle loaders (as kids in the sixties were inclined to do) we figured the ball needed some help - the load ended up as the round ball encased in a 303 cleaning flannel patch, patch fully soaked/rubbed in wheel bearing grease, that then loaded snug down inside the petals of the poly shotcup - we cut the crimp part of the shell off with a sharp knife and off we went to experiment
It looked to have potential so we mounted a rifle sight off a 310 martini cadet on the rib of the shotgun - wow !! that old clunker gun would shoot that rough cast 1oz ball into two little overlapping 3 inch groups at 50 yards - I could cover the whole thing with my hand sideways on the tree we were shooting into - fired into hard eucalyptus the soft ball was recovered flattened to round an inch diameter and a quarter inch thick.
We fluked it first try - but I think with decent sights and a ball that fit reasonable to the bore - three inches at 50 yards would be common enough -- it was fun in the scrub, we decked three or four pigs and a few roos before we went onto other projects.

[GregLaROCHE]

I’m not looking at shooting beyond fifty yards.

Next question would be where you place the sprue. If it is on top, wind force could tend to start turning it and maybe even spinning it. If this spin would help fine, but if not it may be best to put the sprue on the bottom, or cut it off completely.

[pietro]

He did say smooth bore in the original question...........................

Oops...….


.

[725]

A patched RB would fly out of the barrel flat (no induced spin). Once free of contact (patch / barrel), it would be influenced by anomalies on it's surface as it impacts the atmosphere and it's actual center of gravity. A mass always spins around it's center of gravity when acted upon by some other force. Of course the last contact with the barrel would set it off in one direction or the other.

That's my story and I'm stickin' to it.

[GregLaROCHE]

A patched RB would fly out of the barrel flat (no induced spin). Once free of contact (patch / barrel), it would be influenced by anomalies on it's surface as it impacts the atmosphere and it's actual center of gravity. A mass always spins around it's center of gravity when acted upon by some other force. Of course the last contact with the barrel would set it off in one direction or the other.


That's my story and I'm stickin' to it.

That means a good crown is important on a smooth bore as well as other guns.

[mooman76]

Even if it didn't spin, a good crown would be necessary.

[rfd]

"knuckle ball".

[megasupermagnum]

I too always wanted to know. Based on what I know about shotguns, they come out of the gun with some spin, although insignificant. If you don't believe it, just look at all the straight rifled choke tubes out there to stop this rotation. Taufledermaus of youtube shoots slow motion video of slugs, and they do spin. He even has a video proving rifled slugs spin, something like 1 turn in 24 feet. Now I don't beleive this is the slug rifling. Every smooth bore will exhibit some spin, maybe just due to manufacturing defects. While smooth bores look smooth, in reality they are not perfect.

I personally do not believe this spin to offer any kind of benefit, although it is there. The next thing is the knuckleball. I don't know that this actually happens or not. This is where video would be nice. If you look at very blunt shotgun slugs, like the Lee 7/8 oz, they do not knuckleball. But they are are a weight forward shuttlecock you say. I would think you would see the tail wagging to compensate if that was the case, but you don't . Some get a wobble right out of the gun, but the ones that release smooth, fly smooth.

I honestly do not know, but my own feeling is that the ball picks up a spin. It wouldn't be fast, but it wouldn't have to be.

[Maven]

"knuckle ball".

Faulty analogy, Rob as a knuckle ball isn't moving nearly as fast as a RB in a smoothbore at 60 ft. 6 in.