Right under the nail holes.
The wood is to isolate the lower Aluminum tube from the hand.
The high specific heat and low thermal impedance of Aluminum feels cold to the touch at 3000 feet where I hunt.

There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway
The man who makes no mistakes does not usually make anything.-- Edward John Phelps