the guy you were hitting was probably in a kd much smaller than you (kd rnw seems to be a big factor with abducts) or the more likely scenario is the guy was hit already hit lightly or medium, and you hadn't been hit yet at all.
GBP, NW range, RNW Range # of scientists (and of course Sage/Universities) all seem to play a large role. Not to mention the base gains are (understandably) low and seem to round down.
There are plenty of people having success against targets in the 30 scientist range, so Im kinda just going to shake your experience as not being told the whole story on the prov you hit. Being in range and with 51 scientists isn't reason enough for you to be worthy of abducting one of them.