Recomendation

I have a Walther Terrus that used to have a utg 4-16x40 scope on it. when I used this scope on, it gave me two different groups in the same session of shooting. Now took off the scope and it's giving me these kind of shooting at 10 yards with open sights. I just considered myself a poor airgunner so a really expensive scope is out of budget, but I was thinking about probably to get a Hawke 3-9x40 but I'm not sure if it will hold zero due to the recoil, any of you have some experience with this scope in a similar gun?, Appreciate your opinion, thanks
Ruben
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That's 5 shots at 10 yards with open sights