I have a AEG M4A1 and need to downgrade the spring to 330 fps or below for a CQB game. Everytime I look online spring guns show up and not the springs themselves, and I can't find any springs that are 330 or below. Can someone link me to a spring or something that is 330 FPS or below? This would be greatly appreciated. The place requires .20 bbs btw and they must come from their place so heavier bbs will not work. My gun is around 350 fps.