Separate stadia are provided with the reticle, allowing {HEAD ~ the marksman} to gauge {TAIL ~ the angle} subtended by an object of known size to determine the apparent distance to the target 
to gauge
Separate stadia are provided with the reticle , allowing { HEAD ~ the marksman } to gauge { TAIL ~ the angle } subtended by an object of known size to determine the apparent distance to the target
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH