It is not hard to measure the twist rate yourself, just use a cleaning rod with a brush/mop attached. Mark the rod near the handle with a small line, push the rod into the breech until the brush engages the rifling, then mark the rod again at the point where it is up against the back of the action or the end of a bore guide if you are using one, this is your first datum point..
Then as you push the rod watching the first mark, when this has completed a full rotation stop pushing the rod and mark it at the point where you made the first datum mark.
Withdraw the rod and measure the distance between the two datum marks, say that is 10 inches, you then know you have a 1 in 10 twist barrel.
Hope that makes sense.