Air Arms Owners Club

New member (southern Illinois, USA) with a new S410 FAC and have a few questions. When I cronied the rifle using JSB Match 15.89 pellets (rifle filled to 2700 psi) I averaged 741 fps for 13 shots then the fps dropped rapidly.

While the 741 fps isn't too bad I had expected closer to 800 and the short shot string is puzzling. Is this normal, and if not how do I proceed to correct it?

Accuracy is very good.

Thanks for your help - Steve