You can still have fun playing indoor games even if you are all limited to 300 fps. Evike.com shows how it can be in this video. Don't you agree? They want to hear your thoughts... "What happens when you crank down the FPS of Airsoft gameplay down to 300 FPS? More of the fun with less of the pain. When you play Airsoft at lower FPS, you allow more players to experience Airsoft with less of the intimidation factor and more about the fun aspect of Airsoft. Join the conversation: Should all indoor fields reduce their FPS limits to 300 FPS?"
Tactical Shirts Airsoft have a video to share to everyone and it is about CO2 pistols and how to downgrade them to meet the FPS limits, especially for CQB game sites. The howto video is done in Spanish but they have provided English subtitles, so go ahead and click the play button to watch and learn.
Modify-Tech explains the issue of low FPS in AEGs and one cause is can also be the hop-up spring. They present their Tapered Hop-Up Spring in their XTC as a good solution... "There are lots of variables causing AEGs low FPS issue. The air seal is a key point. The hop up spring, though small, accomplishes big as it can pushes the hop up chamber back into the air nozzle to reach a good air seal.
Airsoft Outlet Northwest talks about FPS and the barrel lengths in this video. An interesting watch... "Why would a shorter barrel make a rifle shoot harder than its stock long barrel? Why would that long barrel not affect a shorter rifle's FPS at all? We take a look inside a baffling airsoft tech question and come up with an interesting explanation."