But the
reflection in the barrel was confusing, and it seemed to him that he saw
several lines.
"It's awfully hard just to get that straight," the boy said, "and it's
dazzling, too."
"That man you saw there," answered his guide, as they moved away, "can
tell almost to the width of a thread of a spider's web if a barrel is
straight. Here, too, is another barrel test going on. You see this man
is pushing a soft lead slug which fits the barrel snugly through the
barrel by means of a brass rod. It takes a certain amount of pressure to
push the lead slug through the barrel. Such slight variations in
diameter of the bore as one-tenth of a thousandth can be readily
detected, for if the barrel is smaller at any point than where it
entered, the slug will stick, and if it is the least bit larger at any
point, the slug will slide through too easily. Men accustomed to this
class of work can readily detect an increase or decrease in diameter of
one ten-thousandth part of an inch."
"You certainly have it down fine, Mr. Nebett," Hamilton commented.
"We try to," responded his guide. "Then when the barrel experts have
had their turn, the gun is assembled and goes to the action men.
Pages:
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97