You are welcome, I've been through all this frustration and I am happy to help.
If I understand correctly your issue can be solved by changing the origin(image point) of your gun sprite.
Just double click on the gun sprite and go to the second icon from bottom and you will see a target like icon.
Click on it and then click on the centre of the gun for example.
Now, you will be able to adjust it as you like.
Also, I believe your should change the sprite of the gun completely. This angle doesn't help a lot.