Originally Posted by phloudernow
anyway m120 is about 320 to 350 fps right now, also having a longer inner barrel and other factors also affect FPS,
M120 spring depending on make is alot more than 320fps its bordering on 450 FPS
if your looking for 320 to 350 go with an M90. 360-380= M100, 380-410 M110
these are the speeds of modify springs in stock guns. they go towards and sometimes exceed the high end in upgraded guns. madbull, systema, and other brands of springs have different rating systems but generally near the same.
if you meant a 120% spring your closer to the mark.