It is a phrase taken from rodeo routine-- the bucking bronco, or bull, or the calf for the calf-roping contest is kept in a narrow pen, a chute, until it is released and dashes out to its fate:
"His ride on Bold Lancer started out just like he thought it would. The bull bucked straight out of the chute and slowly came around to the left. Clay remained in position, forward on his b