rate of twist in a barrel

[daniellybbert]

I just bought a gun with a gillard barrel and the previous owner doesnt know the twist rate is there any way to be able to tell
thanx daniel

 

[mooncoon]

use a bronze bore brush with a tight patch lubed with oil. Put a piece of masking tape sticking up like a flag on your ramrod at a measured distance and run the brush down the barrel sort of twisting it and allowing it to follow the rifling as it goes.
You count the number of turns of the flag and measure the distance traveled to get the twist.
You didn't ask but the length of bullet you can shoot is estimated by the greenhill formula --- 150 diameter squared over twist equals length (use inches). Normally the twist is 1" faster than the formula recommends

cheers mooncoon

 

[guntech]

What caliber?