A golf ball includes a ‘dual core’ formed from an inner core layer and an outer core layer. The inner core has an outer surface and a center and is typically formed from a substantially-homogenous rubber composition such that the center of the core has a hardness of about 72 Shore C to about 78 Shore C and a trans content of about 5% to 9%, and the outer surface of the inner core has a trans content of about 5% to 9%. The trans content of the outer surface and the center of the inner core are preferably within 2% of each other and, more preferably are substantially the same to define a zero trans gradient along a radius of the inner core.