Golf club head

1. A golf club head comprising:

a body having a face, a crown and a sole together defining an interior cavity, the body having a channel, the channel comprising first and second opposing ledges extending within the channel;

at least one crown opening and at least one crown insert attached to the body and covering the at least one crown opening;

at least one weight member configured to clamp the first and second ledges at selected locations along the channel, wherein movement of the at least one weight member within the channel adjusts a location of a center of gravity of the golf club head;

the at least one weight member is located entirely external to the interior cavity of the body and comprises an outer member, an inner member, and a threaded fastening bolt that connects the outer member to the inner member;

a coefficient of restitution (COR) feature located on the sole of the golf club head;

a weight installation cavity located in a portion of the channel in which the first and second opposing ledges extend,

wherein the weight installation cavity is configured to allow angled insertion of at least the inner member through an opening within the channel, and the weight installation cavity is one of the selected locations that the at least one weight member is configured to clamp, and

wherein at least a portion of the outer member is disposed within the channel when the at least one weight member is clamped to the first and second ledges;

a heel opening located on a heel end of the body, the heel opening configured to receive a fastening member; and

a head-shaft connection system including a sleeve that is secured by the fastening member in a locked position, the head-shaft connection system configured to allow the golf club head to be adjustably attachable to a golf club shaft in a plurality of different positions resulting in an adjustability range of different combinations of loft angle, face angle, or lie angle,

wherein the at least one crown insert is formed from a composite material,

wherein at least one of the inner member and the outer member are noncircular and shaped to prevent rotation within the channel upon tightening the threaded fastening bolt,

wherein the COR feature has a length and is offset an offset distance from a leading edge of the golf club head, where the offset distance is a minimum distance from the leading edge of the golf club head to the COR feature, and

wherein the face includes a center face location that defines the head origin of a coordinate system in which an x-axis is tangential to the face at the center face location and is parallel to a ground plane when the body is in a normal address position, a y-axis extends perpendicular to the x-axis and is also parallel to the ground plane, and a z-axis extends perpendicular to the ground plane, wherein a positive x-axis extends toward the heel portion from the head origin, a positive y-axis extends rearwardly from the head origin, and a positive z-axis extends upwardly from the head origin.

2. The golf club head of claim 1 , wherein the outer member comprises a central protrusion that extends into a space between the first and second ledges, the outer member further comprising first and second recessed surfaces on opposite sides of the central protrusion, the first recessed surface being configured to contact the first ledge and the second recessed surface being configured to contact the second ledge.

3. The golf club head of claim 2 , wherein when the at least one weight member is secured to the channel, the outer member engages an outward facing surface of the at least one ledge and the inner member engages an inward-facing surface of the at least one ledge, and the threaded fastening bolt has a threaded shaft that extends through a first aperture of the outer member and engages mating threads located in a second aperture of the inner member;

wherein the threaded shaft of the threaded fasting bolt has a shaft axis that extends through both the crown and the sole;

wherein the outer member is noncircular and is configured to prevent rotation when tightening the threaded fastening bolt.

4. The golf club head of claim 3 , wherein the COR feature is a channel and the channel is merged with the heel opening.

5. The golf club head of claim 3 , wherein the face has a face thickness that varies including a maximum face thickness greater than about 3.0 mm, a minimum face thickness less than about 3.0 mm, and the face thickness has a thickness change of at least 25% over the face between the maximum face thickness and the minimum face thickness.

6. The golf club head of claim 1 , wherein the COR feature is a channel.

7. The golf club head of claim 1 , wherein the COR feature is a through slot.

8. The golf club head of claim 1 , wherein adjustment of the at least one weight member within the channel provides a maximum y-axis adjustment range of the position of the center of gravity (Max ΔCGy) that is no less than 2 mm and no more than 8 mm.

9. The golf club head of claim 1 , wherein the body is formed of titanium, and the golf club head has a volume of at least 400 cm 3 .

10. The golf club head of claim 1 , wherein the face has a face thickness that varies including a maximum face thickness and a minimum face thickness, and wherein the maximum face thickness is greater than 3.0 mm, the minimum face thickness is less than 2.3 mm, and the face thickness has a thickness change of at least 25% over the face between the minimum face thickness and the maximum face thickness.

11. The golf club head of claim 1 , wherein the body further comprises a face opening, and wherein the golf club head further comprises a composite face plate received in the face opening.