How can i increase the fps of my airsoft gun?

get a tight bore, instead if increasing fps increase accuracy. If your gun does 400 fps, but it never is accurate enough to hit anything you just lost the game, and many more to come. Get a tight bore like I said and watch the kills accumulate. As long as the gun has at least 300 fps your fine.

basically, if you have a cheap gun like that, you can't (easily) increase the fps. you'd have to spend a lot of money to increase its speed, and you'd have to spend a lot of time finding a place to do it for you. really what you should do is buy a better gun. if you buy a gun from airsoftextreme.com (best website for guns--all their guns are good, and you can get a good one between $200 and $300), then you can get them to upgrade the gun's fps for you. if you're really interested in airsoft, it's worth the money to buy a gun from airsoftextreme cuz it'll last you forever

obviously you can't have tigher springs on the ELECTRIC M4.... but lighter bb's will speed them up some. going from .2g to .12g can speed it up by up to 60fps or so but it will take away some accuracy which on an AEG you need. I use .25g on my L96 sniper and if I go down to .2g at 100yd I can lose 20ft of accuracy. As for the M4 there's not much you can do unless you want to buy internal upgrades for it that will do the job, but they're pricey. The pistol you can buy tighter springs like the other person mentioned but I really wouldn't worry about the pistol.

use tighter springs or lighter bbs