New Hatsan Gun

I got a Hatsan gun for Christmas, but have only put less than 30 rounds through it since then. I've just been too busy. Luckily I've grown up enough to be patient about things like this, and today I spent some quality time with the gun. Photographed is the gun and a group I shot at 60 feet (20 yards). I used the bipod for this group. I found as I was warming up that my groups were not nearly as good shooting with the artillery hold (without the bipod, of course). The gun is a 0.25 caliber and has a gas-spring power plant. How powerful is it? I could have logged more detailed information on it's power, but I did notice that it will shoot cleanly through a stack of about 40-50 sheets of tightly packed copier paper at 30 feet.