Sorry for taking so long to reply the rifle is pre antitamper i believe its a 2007 model ive taken the top allen key screw out and there dont look like any damage to any threads but im no expert ill try sending it for a service and see if they can sort it out because if it has been messed about with...

Sorry im in nottingham

Hi guys im new to the forum so ill appoligise for this being my first post ive recently bought an airarms s400 carbine and i noticed after a few days that is was down on power so i got a friend to put it on a chrono and the best i could get was 9.4ftlb now ive filled it a few time and noticed a leak...