Golf club heads and methods to manufacture golf club heads

A golf club head comprising:

• a body portion having an exterior portion, an interior portion, and a volume of less than or equal to 100 cubic centimeters, the body portion comprising a toe portion with a toe portion edge, a heel portion with a heel portion edge, a front portion, a back portion with a back wall portion, a top portion with a top portion edge, and a sole portion with a sole portion edge, the back wall portion comprising an inner surface, an outer surface, and a first back wall portion thickness between the inner surface and the outer surface;
• a face portion coupled to the front portion;
• a port connecting the exterior portion to the interior portion, the port comprising a port wall;
• a filler material in the interior portion of the body portion and coupled to the back wall portion;
• and
• a plurality of groove portions on the back wall portion, each groove portion of the plurality of groove portions extending into the back wall portion from the inner surface and extending outward from a location at or proximate to the port wall toward a perimeter portion of the back wall portion, each groove portion of the plurality of groove portions comprising a groove portion length, a groove portion width, and a groove portion depth,
• wherein the plurality of groove portions comprises a first groove portion and a second groove portion, the first groove portion and the second groove portion being spaced apart by a portion of the back wall portion located between the first groove portion and the second groove portion,
• wherein the portion of the back wall portion located between the first groove portion and the second groove portion has a second back wall portion thickness that is less than the first back wall portion thickness, and
• wherein a third back wall portion thickness defined at a bottom of the first groove portion is less than the second back wall portion thickness.

An iron-type golf club comprising:

• a shaft having a first end and a second end;
• a grip coupled to the first end;
• and
• a golf club head coupled to the second end, the golf club head comprising:
• a body portion having an exterior portion and an interior portion, the body portion comprising a toe portion with a toe portion edge, a heel portion with a heel portion edge, a front portion, a back portion with a back wall portion, a top portion with a top portion edge, and a sole portion with a sole portion edge, the back wall portion comprising an inner surface;
• a face portion coupled to the front portion;
• a first port connecting the exterior portion to the interior portion;
• a second port comprising a port wall extending into the interior portion of the body portion, the port wall comprising a plurality of spaced apart cut out portions and a threaded portion between each pair of adjacent cut out portions of the plurality of spaced apart cut out portions;
• an external mass portion received in the second port;
• a plurality of groove portions on the back wall portion, each groove portion of the plurality of groove portions extending into the back wall portion from the inner surface and extending outward from a location at or proximate to the port wall of the second port toward a perimeter portion of the back wall portion;
• and
• a filler material in the interior portion of the body portion and coupled to at least one of the back wall portion or the face portion,
• wherein the plurality of groove portions are radially arranged around the second port, and
• wherein at least one groove portion of the plurality of groove portions extends from the port wall of the second port to a location defining a transition portion between the back wall portion and the top portion edge.