Original rifling twist studies?

[Elnathan]

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.

[Mike Brooks]

German (Germanic) rifles were generally one twist in the length of the barrel. That really doesn't answer your question about American rifles though.

[Bill Paton]

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 don’t try it in rough barrels. My method seems to be reproducible within about 1” 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

[Levy]

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

[Elnathan]

Bill,

If you would be so kind. I am sure I'm not the only person who would be interested in that data.