I have purchased a pellet rifle to dispatch pesky squirrels but cannot get the scope zeroed. I have hunted for years and sighted in a variety of rifles and scopes. I have tried several different scopes with the same results. This rifle will group 3 shots in a 2 inch circle but then it will put the 4th shot 6 inches high and the fifth shot 6 inches left. Basically it is all over the place. My question is, are all pellet guns this inconsistent?