HC Rifle twist

[pocono-rick]

Hi all,
Does anyone know what was the common twist rate used on original Pennsylvania rifles ? I shoot a Shenandoah rifle with a 1:66 twist and its very accurate; only good feature of the gun.I have a chance to own a Pedersoli Pennsylvania rifle but I see the twist is 1:47 for the 50 cal.
Why would they use a fast twist on a replica of a rifle meant to shoot patched round balls?

Thanks
pocono

 

[Jumpshot]

I have a Pedersoli Penn., 1:48 twist, I've outshot a bunch of people with it using patched roundballs. I don't know what twist was most common back in the day. I just know mine shoots very accurate today.

 

[Elnathan]

1:48, possibly a few up to 1:60. German rifles were even faster at times. Roughly one turn in the length of the barrel seems to have been about standard operating procedure for the Germans and the Americans, though the Brits seem to have caught on to the advantages of a slower twist quite early.

 

[paulvallandigham]

a 1:48 is not a " fast twist ",so the premise of your question is wrong. It may be faster than your 1:60, but its not considered fast. Also, optimum ROT depends on both caliber, and the projectile being fired. While you can't overstabilize a round ball, you can understabilize a conical bullet. I suspect that these guns are often sold with the 1:48" twist because they shoot RB very well, but can also be used with some of the shorter conicals, too. The longer the bullet, the faster the ROT needs to be. When you are talking about shooting a bullet that is 1.5 times the diameter of the ball in length, or less, it generally will work in the same barrel. Remember also that accepted Muzzle loading ranges are 100 yards and under. We all are exposed to the current hype about shooting deer out at 200 yards with zip guns, shooting modern propellants, modern powders, using modern primers, and scope sites on them, but that does not apply to Traditional side lock and underhammer MLers, using iron sights,real black powder, and bore diameter round balls.

 

[mmahlock]

I don't have any info on American rifle twists but on February 14 1800 rifles were evaluated by the British Army Board of Ordnance with the following twists:

1:51
1:56
1:28
1:37
1:39
1:56
1:52
1:66

Rates of twist at this time were not based on the number of complete rotations over a specific length. They were based on the portion of a full rotation in the length of the barrel e.g. 1/4, 1/2, 3/4, or 1 twist.

Shooting the barrels mounted on a fixed mortar bed they came to the conclusion that a rifle barrel 2-1/2 feet long with a 1/4 twist i.e. 1:120 produced the best group.

Go figure. :surrender:

It also fowled the least.

Given the expense of building or making a rifling machine my guess would be that the rifling of the period was determined by gun maker either by experience or tradition (the twist prefered by the master the apprentice learned from) and one established was used by that gun maker for everything he made. Unless the barrel was made in a factory setting where several rifling machines were available and the buyer could select the twist desired.

 

[Stophel]

I have asked this question over and over again and NEVER gotten a good answer. What I'd like someone to say is "I have this old gun and the twist rate is.....", but so far, the best anyone has told me is "I think about 1 in 48 inches was common".

I'd like actual examples, myself.

I have two old rifles. One is German and from about 1830. About .65 caliber and one turn in about 32" (the barrel is 16" long). The other is a massachusetts rifle from about 1820 with a 41" .58 cal barrel rifled at one turn in about 36" (or maybe I have the two confused and it may be the other way around, I don't remember at the moment.....).

I do know that other German rifle barrels would be faster, maybe one turn in two feet.

 

[Dphar]

Hi all,
Does anyone know what was the common twist rate used on original Pennsylvania rifles ? I shoot a Shenandoah rifle with a 1:66 twist and its very accurate; only good feature of the gun.I have a chance to own a Pedersoli Pennsylvania rifle but I see the twist is 1:47 for the 50 cal.
Why would they use a fast twist on a replica of a rifle meant to shoot patched round balls?

Thanks
pocono

Original twists? Some where between 30 and a 144 inches. No, I am not being a smarta**.
But something between 48 and 72 is likely "typical" for an "American rifle". 66 is right in the middle. I would not want a 48" 54 cal but this twist is near perfect for a 50 cal and will shoot all the powder the rifle will burn and likely will shoot well with reduced charges as well. So long as the grooves are .008-.012 deep. Some factory made barrels may have very shallow grooves and may not shoot well with PRB.
I don't think twists slower than 66 are needed until 58 or 62 caliber and this will be powder charge dependent to some extent.

Dan

 

[Dphar]

1:48, possibly a few up to 1:60. German rifles were even faster at times. Roughly one turn in the length of the barrel seems to have been about standard operating procedure for the Germans and the Americans, though the Brits seem to have caught on to the advantages of a slower twist quite early.

The twists used in American rifles in the 18th century is not well documented as the British.
People reboring and rerifling original rifles (see Cline's book) in the 20th century to make shooters of them further confuses this. Its going to depend on the belief of the individual barrel maker. 48" is not a bad guess.

However the Europeans and the British like "one turn in the barrel" no matter how short it was. A great many larger bore British rifles had twists so fast that they finally had to adopt the "belted ball" to prevent "stripping". It is not unusual to find rifles of 54 caliber (a small bore) with 30" or barrels with one turn in the barrel or even faster by the early 19th century.
Even though the British military had proven a slow twist shot best in testing for the Baker rifle the commercial trade STILL made very fast twist rifles apparently till the end of the percussion era. And even the British Brunswick rifle adopted the belted ball and a 30" twist for a 70 cal rifle which would likely have shot as well if not better with a 6 or 10 ft twist.
The idea among some British makers was that the larger ball needed a faster twist. This resulted in big game rifles such as 10 to 4 bores being twisted so fast as to be unusable with the charges needed for African and Indian big game. As a result many hunters of animals such as Elephant simply used smooth bore guns since they would actually shoot as well or better than an over twisted rifle when loaded to provide adequate penetration on large animals.
See the writings of Selous, Forsythe, George etc. Selous took a horrid beating hunting Elephant in Africa with light weight (under 13 pounds IIRC) 4 bore "duck" guns.

The Americans never went down the fast twist road. Staying, for the *most part* with twists of 4 ft or slower until the advent of the "picket" bullet and then twists were increased to 30-40" or gain twists ending in this range since the 48" will not shoot an elongated projectile of this design all that well.

Dan

 

[CoyoteJoe]

I have asked this question over and over again and NEVER gotten a good answer. What I'd like someone to say is "I have this old gun and the twist rate is.....", but so far, the best anyone has told me is "I think about 1 in 48 inches was common".

I'd like actual examples, myself.
quote]
Yes, that is a tough one. I think very few collector's ever shoot their prized guns and so it is hard even to get information on caliber and whether rifled or smooth, twist?
Two centuries back, nothing was very scientific, many gun builders were illiterate and so were most gun buyers, any discussion of twist would likely just confuse most folks. It does appear that most builders used just one rifling guide for all barrels regardless of caliber and likely the apprentice just copied whatever the master used and very few such machines have survived. Rifling machines found in the Appalachian regions may not be so old as they look since rifles were still being built there in the twentieth century and I don't think the Appalachian gunsmith of 1930 necessarily did everything the way it was done by Pennsylvania smiths in 1800. And, for that mater, there wasn't any standardization among smiths of 1800 either. I think you'd have to survey many hundreds of old guns to come up with even a reasonable generalization.

 

[pocono-rick]

Thanks all!So i guess the 1: 48 twists in the Pedersoli rifle will be fine.Once again you guys answered my question and then some!There is lots to learn and I know I found the right place.

Thanks
Pocono

 

[Stophel]

All one needs to do to measure your twist rate is to put a snug fitting patch on your rod, push it down the bore, mark the top of the rod, and carefully pull the rod out, allowing it to turn following the rifling. See how far it goes to make a whole turn (or a half turn) and you can calculate your twist rate.