What spring airsoft gun should i get?

If I get a new spring for my airsoft gun what else do i have to replace

• i wanna get a new spring to up the FPS . what do i have to get so my gun won't break

• Answer:

  Listen to the last guy there. I will tell you one thing you need, patients. I put a new spring and guide in CM030 Friday and it took me a little over four hours. I was hoping whatever was going to break would hurry up and do it this weekend but nothing did (I put in a 130, way too big for a stock box but I still managed 2,000 rounds through it). I got lucky picking up a new guide. I thought it was a good idea but no way I was getting the stock spring back in there once I saw it. The new metal one fit over a screwdriver and after 8 or 9 tries I actually got it in there without dropping the gears. If you do this you might want to pick up a new piston. That is what will break most likely after looking at it. I am looking at a JBU on AirsoftGI as soon as mine does. Those little nylon teeth can't keep taking that spring.