I've used the sierra 3 scopes and wasn't all that impressed. The optical quality lacked and the reticle was too heavy, I also didn't like that there was no wind hold points below the reticle and so you ended up holding in space.
I haven't tried the sierra 6 but it does look better.
I do however use a 1800bdx rangefinder, paired with the bdx app and a variety of scopes. The rangefinder will show the elevation and windage adjustments needed in the display after it displays the range. I find it works very well and prefer it to a CDS type dial as I can change the environmental data and have multiple profiles for different loads.
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