MIKE GEORGE says:
I shouldnt think there is anything mechanically wrong with the gun. I suspect that the comb of the stock is too low for you, and the best solution is to consult a good gunsmith or shooting coach, then have the stock bent to suit you.
For a DIY approach, you can stick layers of leather, cloth or cardboard to the comb until you achieve the right height.
When you have found it, there are two alternatives: either have the stock professionally bent, or buy one of the commercially available comb raisers.
These usually come in thicknesses of 3mm or 6mm, although there are others.
Google gives plenty of alternatives, and the most expensive seems to be around £34.
Incidentally, when firing at a mark on a pattern sheet, dont squint along the barrel and aim, as you would with a rifle.
Keep your eye on the mark and try to point the gun naturally at it, as you would at a clay target or a bird.
This gives a much truer picture of how the gun is shooting.