Just switched the scope out on my M3 for the Athlon. Wanted a scope that I could dial elevation rather then use hold over reticle like all my other air rifles. So far I’m liking it. Glass is clear adjustments are positive. The zero stop is a nice feature. With my aging eyes it would be nice if the elevation markings were a bit larger. Maybe I’m spoiled by my March scope. Got a great deal from The Optic Zone with free shipping for $525.09. Here’s a picture of the zero stop with the elevation knob removed.
Once zeroed just loosen the three set screws and rotate the brass ring against the stop then tighten set screws back up and reinstall elevation knob on zero marking.