Beware of this fatal flaw in some Second Focal Plane scopes

Using an Athlon Midas BTR Gen 2 as an example, we show a fatal design flaw of some Second Focal Plane (SFP) scopes that renders their reticle subtensions unusable for precision applications. We compare the Athlon to an SFP Vortex Viper that does not have this flaw, as well as a Bushnell T-series spotting scope whose reticle is in the First Focal Plane (FFP).