Most important upgrade for your airsoft AEG

Replacing the hop chamber and rubber on the very old Tokyo Marui M16 made all the difference to it over all performance. This toy has had loads of upgrades within the gearbox but it was being held back by the hop chamber and the answer was not to just put in a stronger spring. Replacing the hop chamber on this occasion made the difference of about 50 fps when using 0.4g bbs.