Diana Mod.5G T01

You can adjust the point of impact by placing some shims under the breech seal. As I recall, the shims are available for purchase, though I forget where, or, you can simply improvise. Which is exactly what I did. 



Maybe cut some thin plastic rings to experiment with? Stiff card stock? Remember, it doesn’t take much, so add a little at a time. Be creative and you’ll solve the problem.