I've spent hours trying to get the fps on my M14 to over 400 with absolutely no success... My compression is good everywhere I can check. I've done the bucking mods using dental floss, and flat hop nub. It's incredibly accurate and consistent with each shot.... Unfortunately every shot slowly glides to the target, it won't shoot all the way through a coke can or the side of a cardboard box. It's ridiculous.... I'm ready to smash this thing and be done with it. What the hell else can be done?? I just put a new m120 spring in to see if the other was maybe worn out and I got zero improvement... Damn it!!!!!