Javi and Cesar  of 0'20 Magazine talk about the lightweight airsoft M249 para AEG in the market today, the S&T M249 Sportline. Apart from being lightweight as it is mainly made of Polymer, this support AEG is also affordable. The metal parts are the barrel and gearbox. It will accept the M4 300-round magazines, box mags made for the M249 AEG, and it has a quick spring change system so you can meet the requirements of your local game site.