Rates-of-twist

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For years I've hunted with a T/C Renegade .50 cal with patched round ball. Until recently, that's all you could use in PA. Now that sabots are legal, I find that those hollow-points do a better job on a deer than the old round ball. Now as to rate-of-twist --- is there any documentation or whatever that explains how a round ball will compare to a maxi or sabot ? As far as drop, velocity,etc. Or is it as simple as using comparable weights ? I think I heard somewhere that a 1-in-66 is best for round balls and the 1-in-48 , for example are better for sabots. Any truth to these examples. I know the ultimate answer is to work on all kinds of loads, etc., but what my objective is, is to use round balls for target practice and just plain shootig, and the sabots for deer huntng only ( too expensive for plinking)
Thanks for any opinions/advice.
Charlie
 

musketman

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quote:Originally posted by charlief:
I heard somewhere that a 1-in-66 is best for round balls and the 1-in-48 , for example are better for sabots.Muzzleloading bullets do require a faster twist (1-in-48) because of the longer bearing surface and greater mass.
The round ball has "LESS" mass and bearing surface, thus requires a slower rate of twist, say 1-in-66 or greater.
I have seen riflings as slow as 1-in-98 twist before...

These rate of twist will also set your min/max loads too... Too fast of a twist can strip a round ball from it's patch before leaving the barrel, resulting in a major pressure leak.

Just like those "HIGH POWERED RIFLES", bullet stabilization is directly related to the riflings, and if a 30.06
shocked.gif
is rifled for a 180 grain bullet or better, then 110 grain bullets will not be as stabile and it will pattern all over the target.

Bottom line, trial and error will tell, you can shoot round balls in fast twist barrels, just not as accurately as with a slower twist.
The same goes for shooting maxi-balls and sabots from a round ball barrel, it will work, just not as good as a faster rate of twist barrel.

Somewhere, there is a "HAPPY MEDIUM" just waiting to be found.
 

Guest
Thank you very much for the good response. I'll do the trial-n-error thing and hope my sabots should as good as my round balls.
 

musketman

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Trial-n-error is a good thing too...
You get to do a lot of shooting.
grin.gif


Remember to take notes...
 

Guest
Some years ago the Alaska Dept. of Fish and Game began a study, since abandoned, of penetration using a variety of powder charges and projectiles. The data still exists here and there but is not readily available. There are plans to resume the study at some time in the future. Meanwhile, the preliminary data does hint as some interesting results.

The test media consisted of a plywood frame containing the test media as follows:
innertube stretched over the opening, to simulate skin, followed by 1 inch of water-soaked telephone books, 1/4 inch plywood to simulate breaking through a rib or scapula, with the remainder of the media consisting of more water soaked telephone books.

Generally, heavy conical projectiles penetrated more deeply than did round-balls but r.b. certainly penetrated well enough to have resulted in fatal wounds to heavy-bodied big game animals. Pistol bullets fired in sabots performed abysmally. So badly that they are not recommended for use on heavy-bodied Alaska big game animals.

The best penetration measured in this test was from a hollow-base, solid-point "buffalo bullet" fired from a modern in-line rifle loaded with 3 Pyrodex pellets.

Surprisingly, black powder cartridge rifles outperformed muzzleloaders of the same caliber and similar load. For example, a .45-70 loaded with 70 grains of Goex Cartridge powder firing a 500 grain conical penetrated entirely through the test media and could not be recovered for examination. The same was true of a .50-90 and .50-110 Sharps.

Round balls performed best at moderate velocities. When driven at velocities much higher than 1200 fps penetration actually decreased, rather than increased. For test guns for which a load had been worked up for optimal accuracy, the most accurate load also seemed to the load that in that gun produced the best penetration.

Ignition system had no measureable impact on penetration. It didn't matter if the gun was a flintlock, side-hammer percussion or modern in-line.

As noted by others, rate of twist has a considerable bearing on rifle accuracy. Round balls like a slow rate of twist while conicals want a fast rate. 1:48 is somewhere in the middle. During the 1970s and early 80s most factory-produced guns settled for that middle ground hoping the compromise would result in a rifle that would shoot either conicals or round-balls well. Unfortunately, most of the guns don't shoot either one worth a tinker's dam.

I generally recommend my customers decide what their primary purpose is for a new rifle, and buy a gun with a rate of twist appropriate to that purpose. If the costumer is a hunter with no interest in living-history then a rifle that shoots conicals well (a fast rate of twist)and if the customer is a living-history enthusiast I recommend a slower twist, round-ball gun.

BTW, there is no reason for anyone to hesitate to hunt large bodied big game with a round ball. They perform adequately at all reasonable muzzleloader ranges.

Also something to consider is that big bullets will not kill an animal any faster or more humanely than small ones. Animals with a slow metabolic rate take a while to die, regardless of what they're hit with. One old Sourdough noted that it takes a moose 3 1/2 minutes to die regardless of whether he's shot with a .22 or a bazooka. Kodiak brown bears take a bit longer.

Swanny
 

Abarnes

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Do the math if your bullet is flying at 1500fps and rotating at 1rev. Per 48 inches 1500÷48=31.25rev/second
31.25×60=1875 rpm
Then figure the weight of your bullet in and the chance of an impurity throwing off the balance
I read somewhere that balls need to spin faster , I think
I would Google rifling calculators they can point you in the right direction
 

Johnny Tremain

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The slower the twist, the harder to load also. I shot a friends 1/72 rifle. a 40 cal that was not fun to load.
I was told decades ago that 1/66 is the slowest you should go. I went with 1/60.
It spins the 45 cal round ball out to 150 yards with good accuracy.
Im happy.
 

mhb

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The slower the twist, the harder to load also. I shot a friends 1/72 rifle. a 40 cal that was not fun to load.
I was told decades ago that 1/66 is the slowest you should go. I went with 1/60.
It spins the 45 cal round ball out to 150 yards with good accuracy.
Im happy.

That is not correct. There is no direct relationship between rifling pitch and difficulty of loading - in fact, if there were, the slower pitch should be easier to load, as offering less resistance to the passage of the projectile and patch. The instance you cite was almost certainly due to a ball/patch/lube combination too tight for the barrel, and/or fouled or rough bore. Rifling pitch necessary to stabilize a projectile is directly related to the length of the projectile, and the roundball is considerably shorter for its weight than most commonly used bullets - the longer the projectile, the faster the pitch needed to stabilize it in flight. Roundball guns do not require fast rifling pitches, and can do reasonably good shooting with quite slow rifling: e.g.: the Forsyth 'bore' guns for roundballs in the 16 - to - 8 bore range, which had a typical rifling pitch of ca. 1-in-114", and shot reasonably well at moderate hunting ranges.

mhb - MIke
 

Phil Coffins

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Depth of rifling also matters. Note the original Hawken mountain rifles had 1 in 48” rifling regardless of bore size. They were also noted for their fine accuracy.
 

LME

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Some years ago the Alaska Dept. of Fish and Game began a study, since abandoned, of penetration using a variety of powder charges and projectiles. The data still exists here and there but is not readily available. There are plans to resume the study at some time in the future. Meanwhile, the preliminary data does hint as some interesting results.

The test media consisted of a plywood frame containing the test media as follows:
innertube stretched over the opening, to simulate skin, followed by 1 inch of water-soaked telephone books, 1/4 inch plywood to simulate breaking through a rib or scapula, with the remainder of the media consisting of more water soaked telephone books.

Generally, heavy conical projectiles penetrated more deeply than did round-balls but r.b. certainly penetrated well enough to have resulted in fatal wounds to heavy-bodied big game animals. Pistol bullets fired in sabots performed abysmally. So badly that they are not recommended for use on heavy-bodied Alaska big game animals.

The best penetration measured in this test was from a hollow-base, solid-point "buffalo bullet" fired from a modern in-line rifle loaded with 3 Pyrodex pellets.

Surprisingly, black powder cartridge rifles outperformed muzzleloaders of the same caliber and similar load. For example, a .45-70 loaded with 70 grains of Goex Cartridge powder firing a 500 grain conical penetrated entirely through the test media and could not be recovered for examination. The same was true of a .50-90 and .50-110 Sharps.

Round balls performed best at moderate velocities. When driven at velocities much higher than 1200 fps penetration actually decreased, rather than increased. For test guns for which a load had been worked up for optimal accuracy, the most accurate load also seemed to the load that in that gun produced the best penetration.

Ignition system had no measureable impact on penetration. It didn't matter if the gun was a flintlock, side-hammer percussion or modern in-line.

As noted by others, rate of twist has a considerable bearing on rifle accuracy. Round balls like a slow rate of twist while conicals want a fast rate. 1:48 is somewhere in the middle. During the 1970s and early 80s most factory-produced guns settled for that middle ground hoping the compromise would result in a rifle that would shoot either conicals or round-balls well. Unfortunately, most of the guns don't shoot either one worth a tinker's dam.

I generally recommend my customers decide what their primary purpose is for a new rifle, and buy a gun with a rate of twist appropriate to that purpose. If the costumer is a hunter with no interest in living-history then a rifle that shoots conicals well (a fast rate of twist)and if the customer is a living-history enthusiast I recommend a slower twist, round-ball gun.

BTW, there is no reason for anyone to hesitate to hunt large bodied big game with a round ball. They perform adequately at all reasonable muzzleloader ranges.

Also something to consider is that big bullets will not kill an animal any faster or more humanely than small ones. Animals with a slow metabolic rate take a while to die, regardless of what they're hit with. One old Sourdough noted that it takes a moose 3 1/2 minutes to die regardless of whether he's shot with a .22 or a bazooka. Kodiak brown bears take a bit longer.

Swanny
I think you have read something that goes against several law of physics? I have read a lot of statements in books that appears to be writen by arm chair shooters. Your last paragraph was totally wrong. Been there done that and the results were different.
 

waksupi

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When you shoot something like buffalo or moose, it does take them several minutes to realize they are dead, and that they are supposed to lay down.
 

bldtrailer

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Green mtn .50 1-70 not hard to load .490 ball 10oz denim mutton tallow lube
DSC03160.JPG
DSC03384.JPG
1-56 Bobby Hoyt 50yrds 490 same lube& patch 60grns sw 3f
DSC03411.JPG
gain twist Bobby Hoyt 96-46? .54 @50yrds same lube 70grns 3ff sw 530 ball same patch (gain twist can shoot rd ball or conical)

There are many ways to skin this cat>>>--> It's more the man than the twist in the rifle>>>-->
take your time at the trigger to work up a good load (grn mtn took me 2yrs to find the load )
Hoyts & getz shot great sooner (but I also had used what I learned with the Grn Mtn)
DSC03033 (2).JPG
 

mhb

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Mike I sure glad what you think out weighs practical use.

This is not an exorcise in theory. It is a determination after use.

I have loaded 1/72, 1/66, 1/60, 1/48.


I make it a rule never to tell more than I actually know. I've been shooting muzzleloaders for 60 years, in calibers from .32 to 11 bore, rifled and smooth, have been a competitor in M/L competition with every class of such arms, and have never found, from that use and experience, any correlation between rifling pitch and difficulty of loading a proper combination of ball, patch and lube. And I do not make broad statements based on a single observation with someone else's rifle and, presumably, components.

mhb - MIke
 
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Old Hawkeye

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I never ceased to be amazed at the lack of understanding about twist rates & bullet stability, especially in the muzzleloading community. The twist rate needed to stabilize a particular projectile has little to do with it's caliber or weight, but rather it's length. The longer a bullet the faster it needs to spin to be stable in flight. Modern pistol or rifle bullets shot in the plastic sabots shot from muzzleloaders have the same twist rate requirements to be stable as they do in a regular barrel without a sabot. A 1 in 48 twist isn't going to stabilize very many modern bullets shot with sabots. 1 in 32 will stabilize a lot of them, but a 1 in 28 or 1 in 24 would be much better. To address the OP's question, you will not find a twist rate that is compatible with both round ball & modern sabot bullets. Just the way it is.
 

Old Hawkeye

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Do the math if your bullet is flying at 1500fps and rotating at 1rev. Per 48 inches 1500÷48=31.25rev/second
31.25×60=1875 rpm
Then figure the weight of your bullet in and the chance of an impurity throwing off the balance
I read somewhere that balls need to spin faster , I think
I would Google rifling calculators they can point you in the right direction
The formula to determine the Rotational Velocity in revs/sec is the twist divided by 12, times the velocity of the bullet. So your bullet going down a 48 twist barrel @ 1500 fps would be spinning at 375 rev/sec or 22,500 RPM. You are using 1500 FEET/sec & dividing it by INCHES. The bullet is spinning once in 4 FEET not 48 FEET. You can't mix inches & feet in the calculation. Wrong formula! The bullet spins once in 4 FEET so, 1500 FEET/sec divide by 4 FEET= 375 rev/sec or 22,500 rpm.
 
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LME

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I never ceased to be amazed at the lack of understanding about twist rates & bullet stability, especially in the muzzleloading community. The twist rate needed to stabilize a particular projectile has little to do with it's caliber or weight, but rather it's length. The longer a bullet the faster it needs to spin to be stable in flight. Modern pistol or rifle bullets shot in the plastic sabots shot from muzzleloaders have the same twist rate requirements to be stable as they do in a regular barrel without a sabot. A 1 in 48 twist isn't going to stabilize very many modern bullets shot with sabots. 1 in 32 will stabilize a lot of them, but a 1 in 28 or 1 in 24 would be much better. To address the OP's question, you will not find a twist rate that is compatible with both round ball & modern sabot bullets. Just the way it is.
One thing that I haven't seen is the rate of burn of black powder. Black powder is almost instant and modern smokeless powder varies. The fact that smokeless powder can be fast burning or slow gives the shooter many options that don't fit well with Black powder users. Some people think the faster a powder burns the faster the bullet. The facts are totally different. Slow burning powder produces more gas therefore more speed behind the projectile.This makes a fast twist just about the only thing we black powder shooters have to get a heavy long projectile stabilised.
 

Old Hawkeye

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One thing that I haven't seen is the rate of burn of black powder. Black powder is almost instant and modern smokeless powder varies. The fact that smokeless powder can be fast burning or slow gives the shooter many options that don't fit well with Black powder users. Some people think the faster a powder burns the faster the bullet. The facts are totally different. Slow burning powder produces more gas therefore more speed behind the projectile.This makes a fast twist just about the only thing we black powder shooters have to get a heavy long projectile stabilised.
Muzzle velocity is a component of Rotational Velocity, but what powder is used to attain that velocity is irrelevant. The bullet is either going & spinning fast enough to stabilize or it's not. So as you say, the limited velocity of black powder makes the twist rate more of a factor. Modern projectiles can be spinning in excess of 250,000 rpm which is 10 times what a smokepole can do with traditional twists.
 

ronaldrothb49

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One thing that I haven't seen is the rate of burn of black powder. Black powder is almost instant and modern smokeless powder varies. The fact that smokeless powder can be fast burning or slow gives the shooter many options that don't fit well with Black powder users. Some people think the faster a powder burns the faster the bullet. The facts are totally different. Slow burning powder produces more gas therefore more speed behind the projectile.This makes a fast twist just about the only thing we black powder shooters have to get a heavy long projectile stabilised.
The burn rat of black powder is anything but instant, that is why the barrels got longer so that more of the powder charge had time to burn. Doesn't matter what kind of powder you use a longer heavier bullet requires a faster twist to stabilize it.
 
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