Author Topic: Original rifling twist studies?  (Read 2068 times)

Offline Elnathan

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Original rifling twist studies?
« on: January 07, 2017, 10:57:12 PM »
I've got a question: Has anyone done a decent study of twist rates in 18th century longrifles? I've heard over the years that the average was something around 1:48, but it would be nice to see that confirmed. Twist is one thing (of many) that isn't usually measured or at least published.

I'm a lot more interested in the effectiveness of what was normal back in the day than I am in what  the potential accuracy of the platform might be, and one of my pipe dreams for many years has been to make a rifle that is as close to the originals in these kinds of mechanical details - twist rate, crown, touch-hole size, etc. -  as I can reasonably achieve.
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Online Mike Brooks

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Re: Original rifling twist studies?
« Reply #1 on: January 08, 2017, 12:52:05 AM »
German (Germanic) rifles were generally one twist in the length of the barrel. That really doesn't answer your question about American rifles though.
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Offline Bill Paton

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Re: Original rifling twist studies?
« Reply #2 on: January 08, 2017, 10:01:05 AM »
I have made a rifling twist gage  which I occasionally use to check the twist rate of Kentucky double rifles for my ongoing study. It requires a reasonably good barrel, and runs a small risk of getting the special jag caught in the bore. For that reason, I rarely dare run the jag all the way to the breech where bad pitting is frequently encountered. And I donít try it in rough barrels. My method seems to be reproducible within about 1Ē in a complete revolution between three consecutive runs in a good barrel, and I need to check some modern barrels with known twist rates to get an idea of accuracy. I usually run 180 deg of twist, measure the length, and double it.

My data sheets are about 4000 miles away from me now, as I am traveling. Not many 18th C barrels in my study, but I have some flint and percussion rifles and some jaegers checked. If asked, I could get data together in February.

Bill Paton
Kentucky double rifle student
wapaton.sr@gmail.com

Offline Levy

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Re: Original rifling twist studies?
« Reply #3 on: January 08, 2017, 06:48:27 PM »
I checked the twist rate of a barrel recovered from the Apalachicola River (ca. 1760-70) and it had a rate of 1 turn in 48".  It also had 7 lands and grooves, was .62 cal. and 38" in length.  I have a military (European) jaeger rifle in .58 cal. with a twist rate of 1 turn in 29", which is the barrel length and agrees with Mike.  My antique .30 cal. percussion squirrel rifle has a twist rate of 1 turn in 72" (go figure).  James Levy

James Levy

Offline Elnathan

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Re: Original rifling twist studies?
« Reply #4 on: January 09, 2017, 03:58:41 AM »
Bill,

If you would be so kind. I am sure I'm not the only person who would be interested in that data.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying...cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. -Robert A. Heinlein