The Seventh Man by Max Brand

Dawn found him over the first crest; at noon he was struggling up the slope of the second range, whose rise was not half so sharp as the upward plunge out of the Asper, but in spite of that easier ground Grey Molly could not gain. She went with shorter steps, now, and her head hung lower and lower, yet when a down stretch opened before her she went at it with a gallop as light, almost, as her race out of Murphy's Pass. Not once had she offered to stop; not once had she winced from the labor of some sharp up-pitch; but still six horsemen hung behind her, and at their head rode a little dusty man on a little dusty roan. It was the lack of training as well as the rough going which held Molly back.

Beyond that second range, however, the down slope stretched smoothly, evenly, for mile on mile and mile on mile; perfect going for Grey Molly over easy hills with patches of forest here and there where he might double, or where he might stop with the hunt sweeping past. All this the sheriff must have known perfectly well, for he no longer kept back with his pack of five, but skirted on ahead, hunting alone. Again and again Vic heard the little shrill whistle with which Pete Glass encouraged the roan. Vic used the spurs twice, and then he desisted from the useless brutality for Molly was doing her best and no power on earth could make her do more. After all, her best would be good enough, for now Vic looked up and his heart leaped into his throat; there was only one more rise above him, and beyond lay the easy ground and a running chance for Molly's slender legs. Even as he raised his head something whined evilly over him, followed by a sound like two heavy hammers swung together, face to face, and shattered by the stroke. A rifle!