If the lock has a "S" shaped neck cock like the one in post # 24 it's a good idea to check to make sure the jaw screw is not bottoming out on the lower part of the "S". If it is, remove the jaw screw and file off the bottom end to provide some clearance.
With the double throat cock like the one shown in post #32, the jaw screw usually doesn't bottom out on anything but it's a good idea to check it anyway.
With the double throat cock like the one shown in post #32, the jaw screw usually doesn't bottom out on anything but it's a good idea to check it anyway.