Hi...the number you have, comes out at early 1924 according to Hillers book, Power wise I have 2, and they run between 525 to 570 fps (neither have been fitted with new springs, but the best one has had a washer set)...so both are below 6 lbs.......I suspect a new spring will improve this, but they are such a sweet, accurate gun, and fine for out to 20 yard plus paper punching (I use R10's/hobbys/finale match) that, although I have a correct,new flatwound spring, I am saving it till the less powerful one is due for some work.