Air Arms TX200 mkIII .177 - Full Power = AA Field Heavy, or JSB Exact Heavy, or Cometa Heavy - 4.52 / 10.34gr
Air Arms TX200 mkIII .177 - 11FPE = JSB Exact Express 4.52

FWB300s - JSB Exact 4.53 - 8.4gr / or interestingly for a low power rifle; JSB Exact Heavy 10.34gr work well.

Above based on best grouping at 25 yards..