In another video I saw that he mentioned 50 meters. I think that is probably the distance he is shooting. I can't really figure out if he is trying to regulate these guns of if he is just testing them with different kinds of ammo. In one he is shooting an 8mm JRS and uses different loads, same for the short barreled slug gun he is seen shooting in another of his videos. If he is regulating them, he must be doing all the tweeking off camera. You will see him mess around with the up and down adjustment some, but that would only effect the placement of both barrels on target. Bob