Rate of rifleing twist?

[Hoboman]

I have a black powder musket that shoots a .58 cal. ball or conical bullet. I would like to determine the rate of twist?? Can't seem to find info on the web regarding this make. Stamped "Sears Roebuck" and it is a reproduction of a civil war Zoauve. So how could I do this myself? Any suggestions would be appreciated.

 

[galamb]

You can figure the twist with your ramrod.

Put a patch or two on the end so that it fits the barrel fairly snug.

Push it all the way down the barrel to the breech.

Wrap a piece of tape around the end that sticking out and put a mark in line with the sight on top of the barrel and mark the muzzle location on the tape as well for a "reference point".

Slowly/gently start removing the ramrod allowing it to rotate as the patches engage the rifling on the way out. When the mark you put in line with the site is exactly at the 6 o'clock position (180 degrees from where it started) measure the distance between the mark you put (where the muzzle was when you started) and how far the ramrod is now sticking out of the barrel.

Then just double the distance (since you are at the "half of one twist point")- so if you are 24" "out" your twist is 1:48 (1 turn in 48") - 35" out would be 1:70 etc.

Typical twists might have been 1:48, 1:60, 1:66 or 1:72 - but it could be something a little more funky, depending on "who" made the barrel.