How to tell the twist of a rifle.
Put a snug fitting patch on the jag and insert the rod in bore. Make a mark
@ 12 o'clock on the rod at the muzzle. Pull rod out slowly until the mark is
@ 12 o'clock and measure the distance from the mark to the muzzle. The resulting measurement is the twist of your rifling, ie. 1 turn in ____".
There could be some slippage between patch and rifling, but this is close enough for government work.