Wade had the advantage.

He was lying prone with his right hand round the corner of the framework.
An overhang of the bough-ends above protected his head when he peeped out.

While he watched for a chance to shoot he loaded his empty gun with his left hand.

The rustler strained and writhed his body, twisting his neck, and suddenly darting out his head and arm, he shot.

His bullet tore the overhang of boughs above Wade's face.