Rate of Twist?

[Mort Scott]

If you buy a muzzle loader used how can you tell what the twist is, I know some only shoot round ball while others shoot several combonations.?

 

Mort, run a patched ramrod all the way down the barrel. Then mark the rod at the muzzle , and the top flat. Pull the rod out til it makes 1/4 turn. Measure the distance it came out, and multiply by four, and that's your rate of twist. A lubed patch works best, and it will also tell you somewhat how well it was cleaned, and if it's rough coming out, how poorly it's been cared for. If the owner won't let you do that I would take a pass as quickly as possible.

Bill

 

[necchi]

http://www.muzzleloadingforum.com/fusionbb/showtopic.php?tid/239243/

 

[illuveatar]

1 turn in 45" is a good rate of twist for both round ball and conicals. Slower turns such as 1:66 ect. should be used for round balls only, a cylindrical shaped projectile will probably tumble end over end since it hasn't enough rotational velocity to stabilize it along the axis of travel.

 

1-45??? New one on me.
Mark

 

[illuveatar]

*1:48, mistype :bow:

 

[roger fisher]

Just as a side note ,I have read that a good many original Hawkens were built with a 1 in 48 twist. Yet they were surly meant for round ball only. Werent they?

 

[dyemaker]

Twist rate is respective of bore size. A 1:48 rate of rotation is fine for roundballs of small size whereas a 1:66 rate might be too slow for them.

 

[Loyalist Dave]

Yes indeed, my .40 is a 1:48, but the same barrel from the same maker in a larger caliber can be as slow as 1:72.


Now Folks, it's not just the rate of twist...

The type of rifling, round bottom or square bottom, the depth of the rifling, the width of the grooves vs. the lands, and the purpose for the barrel ALL influence what rate of twist one might wish.

It was determined by the British Ordinance Board in the 18th century, that a 1/4 turn of the ball prior to exit from the barrel would stabilize the ball sufficiently for their purposes, and reduce the problems of fouling in the barrel because of the slow twist. So the 30" Baker rifle may have orginally had a 1:120 twist rate, for a .610 ball. This was for a military rifle, with much different needs than a target or hunting piece.

The British Enfield was such an accurate rifle it was used for sniping in the Civil War, firing a Minié ball, a conical bullet, with a slow twist rate. Pedersoli repros of the 3-band Enfield are 1:78 twist, but the two band "Naval" rifle and even shorter "musketoon" are 1:48. The Zouve repro has a 1:60 twist, the 1861 Springfield has a 1:72, their 1857 Württembergischen has a 1:55 twist..., and they all shoot conical bullets very well.

On the other side of the spectrum, the Pedersoli Jaeger has a 1:24 twist rate, but launches .530 patched round ball quite well with 70 grains of 3Fg.

So a beginning point is that often one finds that 1:48 twist works ok for patched round ball, and conical bullets, and that slower twist rates such as 1:56, 1:60, 1:66, and 1:72 and inbetween, don't do well stabilizing a conical, but work quite well for patched round ball, especially for heavy powder loads.

LD

 

[Rifleman1776]

Twist rate is respective of bore size. A 1:48 rate of rotation is fine for roundballs of small size whereas a 1:66 rate might be too slow for them.

It has been a number of years since I visited the G.M. Davis Gun Museum in Claremore, OK. I like that museum because they display guns in the manner (I believe) they should be. Chronologically. And, they have a spec. card with each one which includes bore and twist rate.
As I recall, the overwhelming majority of the ml rifles had a 1:48 twist. This was surprising to me. I can only speculate this was because light charges were used most of the time to conserve powder. e.g. in a .50 cal. a 50 grain charge will kill a deer, or indian, just as ded as a 90 gr. charge and it saves hard to get powder.

 

[dyemaker]

I was thinking of modern standards and roundballs. Yes, there is quite alot of difference when comparing twist rates of different
modern barrel makers. Opinion of the correct twist rate varies and sometimes economy (cheapness) plays into it. All rifles in a replica model regardless of caliber being the same twist rate as an example...etc.
I do not know if it is true but I had read that German Jaeger rifles generally had a twist rate of one rotation in the length of barrel? I have no clue why this would be? If this is true the Pedersoli Jaeger with 1:28 twist rate is very close though the rifling is not the same. I would not feel comfortable spinning roundballs that fast when I could use the "optimum" twist rate instead. There is a Pedersoli Jaeger target model with relatively slow twist.

 

[Sperit de bois]

Write the mfg for a copy of the owners manual!!!!!!!!!!!! their free. Been my training( 54 yrs BP) 1/48 is a compromize,,shoot RB and Conicals well,neither exceptional....RB slow rate of twist,,conicals fast rate of twist....ALWAYS go with the MFG,, they built it and know why it was designed/engineered the way it was.

 

[hanshi]

Actually 1-48" twist was a very common twist rate for rifles of the 18th and 19th century. For our purposes "over stabilization" is a myth. A prb in that twist will do just fine unless there's a problem with the ball, patch, lube or powder charge. Conicals can be fussy but ol' prb sure ain't.

 

[William O.]

... Slower turns such as 1:66 ect. should be used for round balls only, a cylindrical shaped projectile will probably tumble end over end since it hasn't enough rotational velocity to stabilize it along the axis of travel.

I call :bull:

 

[DEWB]

From what Iv'e read and heard the Hawkens did use a 1-48 twist but they had deeper grooves than alot of the newer stuff like TC that uses button rifling on there 1-48 barrels. And yea the Hawkens shot round balls although I think I read somewhere that they did make a few that shot conicals but I don't know what the twist was.

 

[illuveatar]

Are you saying that a slow twist won't cause a bullet to tumble, or are you saying that bullets don't tumble at all ?

 

[Dr5x]

I've always Understood that the faster twist barrels can be used with elongated bullets which have more metal bearing on the rifling and can therefore take the stress of the rapid spins.

Shooting a round ball in a fast twist barrel with only the belt around the ball bearing on the rifling will result in that belt being ripped away and causing interesting effects on target if it gets there at all.

Most of your inlines are fairly fast twist and are difficult to use with patched round ball. Its possible but difficult I'm told.

Dutch

 

[hanshi]

FWIW, I fired T/C Maxi balls and Maxi Hunters through a .54 with 1-66" twist and a .50 with 1-66" twist. I did this as an experiment only since I use prb exclusively. I found that at 50 yards - didn't test beyond that distance - accuracy was satisfactory and adequate though not inspiring. There was no sign of tumbling, the holes were crisp and round and groups under 3".

I don't care for conicals and only shoot and hunt with prb. Good to know, however, that I have a backup should I need it.

 

[Rifleman1776]

Are you saying that a slow twist won't cause a bullet to tumble, or are you saying that bullets don't tumble at all ?

I don't know what he means but a slow twist will not stabilize a bullet. Fast twists will stabilize a bullet but different rates are needed for different calibers and lengths of the projectiles. A very tricky subject.
But round balls will stabilize with (relatively) fast twists. 1:48 is considered good, and, for some, the fastest for a rb. However, some pistols have modern gun twists (e.g. 1:20; 1:12, etc.) and I have seen championships taken with these. But, I'm sure the charges used were very light.
In a rifle with 1:48 and prb it takes some trial at the bench to find it's 'sweet spot' most accurate load. Slower twists in rifles are more forgiving.

 

[illuveatar]

I only shoot prb so my bit about conicals comes only from what I've heard on this forum.

I don't know much about maxi balls but if they're like Minie balls they are stabilized in part due to their center of mass being ahead of the center of pressure. The hollow cone at the back end of the Minie acts like a tail or drag which prevents the bullets from wobbling much in flight.

I understand that their are some combinations of bullets and slow twists which achieve excellent accuracy. I was speaking generally and I'm certainly not a lexicon of load, ball and caliber data.

But check this photo out

:shocked2: