Today I shot my Hatsan 135 .30. It is fitted with the SeeAll Mk1 sight. Here is my first six from 30+ yards.
Where? Sorry, I don't see a link. Just your text. Thanks.
(Edit: It's all fixed now. For some reason the site isn't showing me the edit option, so I had to do it this way).
Yes, I see it now. It's a target with six shots. It seems to be a case of vertical stringing, unless you were shooting at different distances, or deliberately aiming that way.
That's a break barrel gun. Vertical stringing isn't that unusual, especially in a new rifle, but sometimes there's something you can do to help.
Sometimes the barel pivot is just too tight because it's brand new, and breaking in the gun by opening and closing the barrel several times, making sure there's a dab of grease or some type of lubricant on the detent and the part it rests against, will take care of it.
But, if enough time goes by and you've already taken quite a few shots, and it hasn't improved, you may actually have to adjust the pivot bolt itself. More is not necessarily better, so make very tiny adjustments, and retest.
So, there's my expert armchair diagnosis. LOL. You may have simply moved the rifle off-target before you pulled the trigger. Or, maybe you were using a rest that wasn't completely firm and stationary enough. There may be nothing wrong with the rifle at all. Some practice with the thing may turn you into a real, 1st class marksman with it.
Have fun! Thanks for the report, especially with the photo to go along with it.
Oh, wait, I may have missed the most important thing. What kind of ammo were you using? This whole slugs-in-springers thing is pretty fascinating to me.