Take your cleaning rod with the patch tip.
Use a patch big enough to fit very snugly in the bore; just loose enough for you to push it through. When the patch engages the rifling, put a mark on the top of the cleaning rod with a felt tip pen near the rod's handle and where the rod enters the bore (either the muzzle or the rear of the action). As you push the rod into the rod into the bore, watch the mark near the handle rotate around. When it is at the top again, put another mark on the rod where it enters the bore. When you measure the distance between the two marks that is the twist rate. That's one way to do it with what you've got at home.
Good luck, Vince
