Throw on a muzzle loader is measured from C/L of the tumbler to center of top of nipple. Throw on a Centerfire breech loader is measured from C/L of tumbler to center of rear of firing pin.
I would assume throw on a pinfire would be C/L of tumbler to top of pin. Note that in all cases this is center of rotation to center of Striking point.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra