I have and use a Vortex HST 4-16 and 6-24 both track well to 1000 yards and hold zero perfect. The 4-16 is on a SPS tactical 20" .308 and this year alone it has helped harvest 4 deer and a cow elk out to 638 yards. I have the 6-24 on my 6.5x284 and last year with that combo it took three deer...