I have taken about a dozen Groundhogs some 10 to 12 pounds with the Diana 36 .177 shooting at 13.7 to 14.1 FPE depending on the pellet. Distance 21-23 yards. The 36 was fully tuned by Gene with JM kit and a hair trigger, a pleasure to shoot and a tack driver. These days I prefer to use a PCP and a lot of FPE too, but I am slowly going back to trying less FPE and more precision. Last year I took several Groundhogs (single shot kills) using the Disco .22 exclusively. I had the Disco dialed down to 25fpe, 785fps w/JSB 18.1gr. It's most accurate with the power adjuster turned mostly out. They dropped just the same as with the ones I took with the Condor .25 at 75+fpe.Here is a pic of the Diana 36 .177 with its trophy: a very chubby 11+lb groundhog.