How Do You Measure The Amount Of Twist A Barrel Has?

[Tim Crosby]

 I've got a .62 Rayl barrel that is 36". A tight patch down the bore on a rod makes about, as best I can figure a shade more than 1/2 a turn as it is pulled out. How do I figure the twist or can I with this info?
 I hate word problems.

    Tim C.
 
 

[J. Talbert]

I’d pull the rod out until it makes 1/2 revolution.  Measure that distance and double it.

You must show your work for full credit.   

Jeff

[Bob McBride]

Here’s how I do it Tim, just as JT described.

[T*O*F]

It's a simple math ratio:

amount ramrod turns/distance pulled = 1/X  You can pull the ramrod any distance you choose.  Partial turns can be broken into 16ths by using flats and corners of the barrel as indicators.

example:
ramrod make 1/2 turn in 24 inches

.5/24 = 1/X
.5X = 24
X = 31.0

[Tim Crosby]

  Thanks guys, 33" at the half so I've got 1 in 66.

     Tim

[flinchrocket]

It's a simple math ratio:

amount ramrod turns/distance pulled = 1/X  You can pull the ramrod any distance you choose.  Partial turns can be broken into 16ths by using flats and corners of the barrel as indicators.

example:
ramrod make 1/2 turn in 24 inches

.5/24 = 1/X
.5X = 24
X = 31.0

This must be some new math. 1/2 turn in 24” would be 1 in 48 twist.

[flinchrocket]

   
      2(.5/24 =1/48

[T*O*F]

1/48 = .5/X
X=24

Arrange the above so 48 is the unknown.  It's gotta work in the reverse.  What's out of place?

[flinchrocket]

The way I understood your computation, you was saying X=31 or 1 in 31 twist for your example.

[Birddog6]

Good lord guys ! 🙄   Obviously it’s a Flintlock barrel. Forget all that math junk & jes use a flint ! 

Get you favorite cleaning rod out that has a bearing in the handle.
Put a Tight oiled patch on a jag & shove it down the bore.
Take a 3/4 flint & tape it sharp side Up to the rod, right at the muzzle.
Pull the jag out of the bore til the flint points Down.
Measure the distance from the muzzle to the flint.
If it is 24” x 2 = 1-48 twist
If it’s  33” x 2 = 1-66 twist
If it’s  35” x 2 = 1-70 twist

Actually I just take a 1” piece of electrical tape around the rod & leave the ends
Sticking up like a flag. It is imperative you have a tight fit on the jag. And easy
if you have a cleaning rod with a bearing in the handle.

[T*O*F]

The way I understood your computation, you was saying X=31 or 1 in 31 twist for your example.

Actually, you are correct.  I don't know how I came up with that answer.  I was using Chisanbop for my computations. 

[Bob Roller]

What I did a LONG time ago was to take a 6 foot long brass rod 5/16"diameter and calibrated it in one inch increments and then made a jag for a patch and a pin that was always lined up with the top flat assuming that it did have sight slots to establish a "top".Push it thru and then add the inch calibrations to whatever sticks out.
60 inches long and 12 inches seen equals a 1 in 48.

Bob Roller

[Frozen Run]

Don't forget to check for gain-twist rifling.

[flinchrocket]

The way I understood your computation, you was saying X=31 or 1 in 31 twist for your example.

Actually, you are correct.  I don't know how I came up with that answer.  I was using Chisanbop for my computations. 

I guess that would work as long as you weren’t missing any fingers.

[Daryl]

Actually I just take a 1” piece of electrical tape around the rod & leave the ends
Sticking up like a flag. It is imperative you have a tight fit on the jag. And easy
if you have a cleaning rod with a bearing in the handle.

Exactly: I use the tape as well.
There is nothing difficult about this, boys.
Even if the rod does not have a bearing, the patch attempt to turn the rod if you let it.