Twist in Barrel?

What does the twist in the barrel mean? I have came across many different "twists". For example is it better to have a 1 in 60" twist or a 1 in 32" twist? Does this have anything to do with what kind of bullet or ball you can shoot? I am just "researching" and trying to educate myself before buying a Flintlock. Thanks for the help!!
~PaDeerHunter~

 

[Stumpkiller]

Does this have anything to do with what kind of bullet or ball you can shoot?

Yes. A slower twist (like 1 turn in 66" in a .50) would be better for round ball than a faster (like 1:32") twist. Faster twists work better for conicals, but you don't want them. A slower twist can also mean the ball has to be driven faster for optimal performance. So a moderate load in a .54 might do better with a 1:66" twist while a heavy load would do better with a 1:72" twist. Ain't nothing ever easy.

BUT, it is relative to ball size. 1:48" is a slow twist for a .32 caliber rifle, while a .58 caliber might do best with a 1:72" or 1:80" twist.

Someone here has a formula to give the optimal twist for round balls of a given size, but for general purposes a 1:66" or 1:72" is common for .50 and .54 caliber rifles. Barrel makers like to have few tooling set-ups and changes, so you're not going to get a 1:68-3/16" twist even if it is the optimum for your caliber. :winking:

Lots of production guns use a 1:48" twist as a compromise to shoot either conical or round ball.

 

[shadyrest]

pittsburgh guy here all twists will shoot the caliber desired just with varying degrees of accuracy 1 in 60, 1 in 66, 1 in 72 etc, have a twist designed for optimum accuracy with roundballs, although i have a thompson pa hunter thats a 1 in 66 that shoot maxi balls best, 1 in 48 is more likely to shoot maxi balls the best. Guys have varying degrees of accuracy with round balls and sabots with this twist. 1 in 32, and 1 in 28 are suited best for sabots will shoot maxis depending on the load/gun/maxi combination. The biggest thing with muzzleloaders is to get out and try different loads with different types of ammunition to find what shoots in your gun the best, muzzleloaders are tricky sometimes, but real fun when you tackle it

 

[Bushwhacker]

On pistol barrels of 12" length I use a 1-20. Most of my rifles are 1-48.. My smoothie is 0-42 haha :redthumb:

 

[Rebel]

Now how can your smoothbore be a 0-42 when mine is a slow twist 0-39? :crackup:

 

[Zonie]

What does the twist in the barrel mean? I have came across many different "twists"....
~PaDeerHunter~

Although you got a lot of answers about twist rates and what they are good for, I'm not sure anyone really answered your first question.

I'm going to assume you meant exactly what you said so my answer to this is as follows:

The thing that seperates a rifle from a smoothbore (like a shotgun) is the grooves inside the barrel known as rifling.

These grooves serve two purposes in a black powder gun.
They serve as areas for the fouling from the blackpowder to go when the next ball and patch are loaded, and they impart a spin to the ball or bullet.
The spin stabilizes the projectile so that it will fly in a relatively straight line. This gives the rifle extra accuracy which the smoothbores do not have.

When they machine the rifling, it is done on a special machine which rotates the cutting tool as it moves thru the bore. The amount of rotation is usually given as the distance traveled along the bore to make one complete revolution of the tool.

This distance is what people are talking about when they talk about "twist".

If you see a twist rate of 1:66, it means the bullet or ball rotates once every 66 inches as it travels downrange.
A twist of 1:48 means one rotation every 48 inches (4 feet).

I hope this answer helps explain what "twist" is.

By the way, the very early "rifles" had the grooves but they didn't "twist". They were straight and served only to provide a place for the fouling to go during loading.
Later it was noticed that machining twist into the barrels inproved accuracy a great deal over the straight grooves or smoothbored guns.

A lot of theorys about why twist made the rifle so much more accurate were proposed.
Among these was:
The spinning of the ball throws the gremlins who would missguide the ball off of it. (Thought of by pro gun, pro accuracy military types).

The forces of good cannot grasp the spinning ball in order to deflect it from its deadly goal. (Thought of by anti gun, anti violence clergy types).

 

[Bushwhacker]

Now how can your smoothbore be a 0-42 when mine is a slow twist 0-39? :crackup:

WAUGHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhh Guess I need to cut mine off some :blah:

 

Here's another fly in the ointment in regards to slow versus fast twist. Many early Germanic rifles had very fast twists like 1 in 24" and did a fine job with roundballs as does the Pedersoli Jaeger with the 1 in 28" twist ( although they now offer a much slower twist as well ). That 1 in 28" had no trouble bustin' Tootsie Roll Pops off their sticks at 15 yards and I'm no sharpshooter by any means. I've read volums of stuff about fast twist for conicals and slow twist for roundballs blah blah blah by Sam Fadala and other experts and scientific minded authors writing articles for magazines and books funded by vendors of this and that but I'll share with you my thoughts on all of it: Phooey! With a snug ball/patch combo and deep enough rifling that faster spinning roundball is a stable son of a gun. I found this to be true by doin' it and not readin' about. Maybe others had different experiences with this but not me. It's easy to read something and accept it for fact but I wouldn't do it too often if I were you. Of course I am from the Show Me State. I may be blasted off the forum for this blasphemy but I'll take my chances.

 

[jim gray]

Now how can your smoothbore be a 0-42 when mine is a slow twist 0-39?


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WAUGHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhh Guess I need to cut mine off some
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:hmm:Rifled or not something must be twisted, here. :crackup: :thumbsup:

 

[Russ T Frizzen]

I've found over the years that when using a rifle with a twist that is supposed to be too fast for patched balls, finding the right powder charge can go a long way toward tightening groups up. Depth of grooves may be of some importance, too. I'm not 100% sure on that one yet.

 

Not much is 100%. My thoughts on deeper rifling is it grips the ball/patch better with more bite and keeps it from skipping the grooves on it's merry way down the bore and like you said, a fellow needs to work out a proper load for accuracy for his particular rifle regardless of the twist." Russ T Frizzen" that's the coolest name on here! By the way, what's the twist on your favorite rounball gun?

 

[jim gray]

I agree, Russ, I think any gun can handle a PBR with the right combination of patch, ball, powder, and charge. In my experience though faster twist means less powder, but that's probably not always the case.

 

[Russ T Frizzen]

My .62 caliber New England long rifle has a 1 turn in 66" rate of twist. This is in a 42" barrel. I can vary the powder charge from 60 to 100 grains and still stabilize the ball. 80 grains is what I generally use, though. It is a Colerain barrel with the round bottom grooves and is a snap to clean. Accuracy is very good and it has never cut a patch.

 

[musketman]

My 1838 .69 caliber smoothbore was rifled with a 1:98 twist in the year 1847, they used two wide shallow grooves parallel to each other...

 

My Colrain Jaeger barrel is 31" and has the 1 in 66" as well . Gotta love that round bottom groove! Musketman, sounds like yours is just this side of being straight. How does the old girl shoot?

 

[BLAHMAN]

There is actually a formula for figuring out rate of twist...I think it is called the "greenhill formula". I have it written down somewhere in my notes...I'll try to find it.

 

[rayb]

There's been some discussion on the Greenhill formula in one of the topics here. Do a search for Greenhill on this forum. Seems that the "150" term has been sort of updated with "130", otherwise formula remains same.

rayb

 

[Stumpkiller]

A formula that relies on an arbitrary multiplier falls under the category of "SWAG" (Scientific Wild-Arse Guess). It can be made to produce whatever result you desire by manipulating the multiplier. :hmm:

I prefer the empirical approach of measuring the distance between holes in paper downrange and asking barrel-makers what has worked for their customers.

 

[Carl Aldridge]

I prefer the empirical approach of measuring the distance between holes in paper downrange and asking barrel-makers what has worked for their customers. [/quote]I like that approach Stumpkiller that seems to be the most practical so far.

 

[brpc]

Folks:

I very much agree with Sam that there is a lot of variance reference what twist will shoot what best.

I have just set out to develop a low cost "training load" for a 1:28 NEF sidekick. Amazingly (at least for me), I found that 30 grains of 777 with an over powder patch pushing a .490 roundball would shoot one inch groups at 50 yards. The point of impact was about 5 inches higher than the hunting load of 80 grains of 777 and a No Excuses 495 grain conical.

I realize that this is not the proper forum for this type gun, but i think that it illustrates the old maxim that
" you don't know until you try."