Smoothbore rate of twist?

[flntlokr]

I don't know that; the recovered slugs only demonstrate that they did not travel as a knuckleball. I'd wager that someone at some point has studied this at length...

I have pondered on that a lot, and have come to the idea that ball irregularities are the root cause of smootbore inaccuracy at distance. Reasoning: when the ball is going very fast as it leaves the muzzle (like a non-spinning baseball), it captures a cone of compressed air behind which it travels. As the ball inevitably slows due to air friction, the cone essentially disappears, and any imperfections in the non-spinning ball will cause uneven friction, causing one side of the ball to slow down, thus imparting a non-predictable curve to the trajectory. If the ball is perfectly aligned with the sprue front or back, the sprue should affect things very little, or not at all. The smoothbore shooters whom I Have seen repeatedly hit small targets well beyond 50 yards, pretty much all roll their ball to smooth them, or are very careful to center the sprue.

 

[Art Caputo]

….The Magnus effect occurs only when the projectile is spinning, doesn't happen with a smoothbore………

I don’t believe this statement is correct.
The Magnus effect can occur whether the projectile is spinning or not(but in a more controlled state if spinning). It is caused by gas(air) forces on the sphere while in flight, ….as is the case with a ball fired from a smooth bore.

 

[George]

I don’t believe this statement is correct.
The Magnus effect can occur whether the projectile is spinning or not(but in a more controlled state if spinning). It is caused by gas(air) forces on the sphere while in flight, ….as is the case with a ball fired from a smooth bore.

Read up on it. You will find that it is defined as an effect on a spinning object, and that it doesn't happen on a non-spinning one.

Spence

 

[Gordoncourtney]

Ha ha nobody hits much at distance with a smooth bore I have tried it ..... for years I rifled barrels with a twisted bar then a machine today I am lapping a bore oval with a 1-110” twist. So far this week I have .005” of oval I’ll do a bit more it’s quite easy. I use a machine but a square twisted bar in a square hole will do. I made the oval lap of aluminium split down the middle with a wedge Watch this space

 

[French Colonial]

So....
If you are shooting swaged balls from your smooth bore with a fairly tight patch you have no sprue and no imperfections and its not bouncing from side to side in the barrel, thus it can shoot more accurately and wouldn't it be interesting to then shoot a ball with a sprue from the same barrel to see if accuracy suffered.

 

[Art Caputo]

Read up on it. You will find that it is defined as an effect on a spinning object, and that it doesn't happen on a non-spinning one.

Spence

I stand corrected….

 

[andy52]

I've taken a couple of deer with a 12 ga and round ball but never even though the ball would have a spin that would impart some sort of stabilizing factor. The only way that could happen would be with a forester style slug that has fins that engage the barrel, those I have used in muzzleloaders and they are a bit more accurate.

 

[George]

Ha ha nobody hits much at distance with a smooth bore I have tried it .....

That settles it then, it's impossible.

today I am lapping a bore oval with a 1-110” twist.

I assume that is a smoothbore you are lapping? What kind of ball will it shoot?
Spence

 

[hanshi]

The accuracy with prb in my smoothbore is good. But it wouldn't surprise me to learn that it wobbled a bit between the muzzle and the target. Spin? No.

 

[Gordoncourtney]

.6" round ball. Tap it in and a bit of lead comes off.....a little push and it glides down the bore , even now I can feel it twisting the push rod....its early days But amazed how simple the operation is......just takes time and patience. I have a half hour go each day and it gets .0005" bigger .Lancaster did .006" oval bores so I'll go for .008" of oval then finish with fine compound. Should be done by end of week.....watch this space.... I might add, for years I used a square twisted rod through a square hole.....just keep it simple.

 

[Gordoncourtney]

Hello Hanshi you got in before me, nice comment.......I am trying ha ha Love from uk Gordon

 

[waksupi]

Weigh your balls. A void in a ball can cause it to do all sorts of mysterious things.

 

[Brokennock]

That settles it then, it's impossible.

I assume that is a smoothbore you are lapping? What kind of ball will it shoot?
Spence

He is attempting to circumvent Britain's laws regarding rifles.

 

[Brokennock]

Ha ha nobody hits much at distance with a smooth bore I have tried it .....

Really? Nobody?
Because you can't, nobody can?
Narcissist?
Spence has posted success at ranges longer than the typical smoothbore expectation,,, achiever through meticulous load development. So have a few others here, and several others on the ALR forum.
On what, other than your own personal experience, do you base your blanket statement on?

 

[Gordoncourtney]

He is attempting to circumvent Britain's laws regarding rifles.

No not circumventing laws I am interested in ways our forefathers did things, at 78 I don't shoot anymore, I thought it a challenge to make a tube with an oval bore, which I can pass on to the younger generation perhaps like yourselves....I found Lancasters oval bores interesting and so little us written about them........no problem

 

[Gordoncourtney]

Really? Nobody?
Because you can't, nobody can?
Narcissist?
Spence has posted success at ranges longer than the typical smoothbore expectation,,, achiever through meticulous load development. So have a few others here, and several others on the ALR forum.
On what, other than your own personal experience, do you base your blanket statement on?

I put that question before, I lived in Nigeria way back , 12 bore slugs and balls were not much good over 20 yards.....shot a lot.......however reading your forum and the enthusiasm of smoothies, it's seem patch balls in smooth bores are far more accurate , say can you hit a tin can at 80 yards, I find it an interesting subject....it's illegal to shoot round balls in shotguns without an S1 police certificate...almost impossible to get, I might add.....

 

[smo]

The proof is in the pudding’…

RIP Mr. Tip

 

[Brokennock]

say can you hit a tin can at 80 yards,

Probably. My load development has produced a load combo that could do the job.
But, alas, I can't see a tin can at 80 yards anymore. At least not under field conditions. Maybe in an empty parking lot or short cut grass field like a football field, lol.

 

[Britsmoothy]

Besides, what is the point of hitting a tin can at eighty yards?
That said I have myself see impressive grouping at 50yds that some riflemen would be happy with!

Our friend needs to be careful. At least one person likes to talk to his local constabulary on here!!

If our friend is rifling an open ended tube or an original without intention of shooting it he is fine.
If he puts a breach plug on one end of the tube or is modifying a contemporary reproduction muzzleloader or breach loader he may be in a legal minefield.
I wish him the best of luck though because I think British firearm law is a little bit pathetic around muzzloaders from the get go!

 

[Gordoncourtney]

That's amazing shooting with a smooth bore I would never have believed it....super photo thanks for the effort, realy appreciated .....and the legal tip , difficult to fine right legal balance of conversation, I have too much enthusiasm for your forum, brilliant conversations, at 78 I could not get my shotgun S2 cert renewed, let alone for a muzzleloader ,it's all down to theory and dreams now in the uk propped up with a 12 ft lb pop air gun, there's little hunting in the uk anyway , I have my own 50 yard garden range I used to belong to the muzzle loaders at Bisely years ago I just collect and repair wall hangers and fight the cancer within me.....there have been great times.......the locals in Nigeria made their own muzzle loaders perhaps they knew more than me.....its been a great life........super forum and chat many thanks