Significance of .36 Caliber Revolver

Some time during one of the battles, Charley kills a Confederate officer with his bayonet. He takes the officer's pistol and keeps it in perfect condition, even after the war when he is back home in Winona. One day, he goes on a picnic, hobbling on his cane to the river. As he opens his sack of food this loaded revolver falls out too, and Charley picks it up. He contemplates suicide, but he does not kill himself and finally puts the gun down.