The horse hesitated, taken unaware by the onslaught.
When he started to run Stopper was already passing him, turning sharply to the right again so that the rope raked the horse's front legs.

Two jumps and Stopper had stopped, faced the horse and stood braced again, his ears perked knowingly while he waited for the flop.
It came--just as it always did come when Stopper got action on the end of a rope.

Horse and rider came down together.

They would not get up until Bud wished it--he could trust Stopper for that--so Bud walked over to the heap, his gun ready for action--and that, too, could be trusted to perform with what speed and precision was necessary.

There would be no hasty shooting, however; Buddy had learned to save his bullets for real need when ammunition was not to be had for the asking, and grown-up Bud had never outgrown the habit.
He picked up the fellow's six-shooter which he had dropped when he fell, and stood sizing up the situation.
By the neckerchief drawn across his face it was a straight case of holdup.