Hi ya Whitebear,
I don't know any details on what your barrel fits, but you can get pretty close on the twist by running a ramrod with a snug patch down the bore, make an index mark on the rod and the muzzle, then as you pull the rod back out, let the rifling spin it and count the revolutions, or partial revolutions. Then it's a math problem from there. 1/2 turn equals 1:64, 3/4 turn equals 1:48. Hope this helps.
-Ron