scopes are very personal, as is magnification. On a bolt gun at 6.5 CM, I think you will like somewhere between 18x and 25x. Given the scope you have, and what I might infer from your budget, you should seriously consider the Nightforce NX8 1.5-20x. A Leupold Mark 5 at 3-18x might also be worth considering, as well as the ATACR 4-16x.
We sell a good number of ATACR and NX8 scopes, if interested. We take scopes in trade, but we stick to a few main brands, and you would do better to sell the SWFA scope and buy a Nightforce or Leupold.