Golf irons with sealed undercut

1. A golf club head comprising:

a body comprising a face, and a rear wall, wherein;

the rear wall is opposite the face;

a rear recess is defined where a portion of the rear wall is recessed into the body toward the face;

a first insert comprising a front surface, a rear surface, and a perimeter, wherein;

the first insert is received within the rear recess such that the front surface is in contact with the rear wall;

the rear surface is opposite the front surface;

the perimeter comprises a topline portion, a lower portion, and a toe-side portion;

a portion of the rear surface is recessed into the first insert towards the front surface, thereby defining an open cavity, wherein;

the topline portion, the lower portion, and the toe-side portion of the perimeter circumscribe the open cavity;

the first insert further comprises a reinforcing feature comprising a beam comprising a first end near the topline portion and a second end near the toe-side portion of the perimeter;

wherein the beam extends across the open cavity between the topline portion and the toe-side portion of the perimeter;

the first insert is formed from a first polymeric material;

wherein the first polymeric material has a hardness, measured on the Shore D scale, between 75 D to 90 D;

the body further comprises a sole, wherein the face, the sole, and the rear wall define an undercut volume;

the rear wall defines at an upper edge thereof a threshold surface defining an upper threshold of the undercut volume, and a sloped ledge adjoining the threshold surface and projecting at an obtuse angle from the threshold surface into the undercut volume;

the golf club head further comprises a second insert between a rear surface of the face and the sloped ledge of the rear wall within the undercut volume to thereby define a fluidly sealed empty cavity within the undercut volume; and

wherein the second insert includes a top surface and a sloped surface projecting at an obtuse angle from the top surface, the top surface of the second insert being seated against a bottom perimeter of the first insert, and the sloped surface being seated against the sloped ledge of the rear wall.

2. The golf club head of claim 1 , wherein the rear recess is recessed into the body via a recess wall and a recess floor, wherein:

the recess floor is proximate the face; and

the recess wall forms a perimeter of the rear recess and is in contact with the perimeter of the first insert.

3. The golf club head of claim 1 , wherein the reinforcing feature extends from the upper threshold of the undercut volume to a topline of the body.

4. The golf club head of claim 1 , wherein the second insert is in compression between the rear wall of the body and the sloped ledge of the rear wall.

5. The golf club head of claim 1 , wherein the second insert is adhered to the sloped ledge of the rear wall.

6. The golf club head of claim 1 , wherein the first insert defines a width, measured normal to the face, and the width varies around the perimeter.

7. The golf club head of claim 1 , wherein the second insert is formed from a second polymeric material.

8. The golf club head of claim 1 , wherein the first polymeric material has a resin content of greater than about 50% by weight.

9. The golf club head of claim 1 , wherein the reinforcing feature has a tensile strength of greater than about 250 MPa.

10. The golf club head of claim 7 , wherein the second polymeric material has a hardness, measured on the Shore A scale, between 40 A to 60 A.