The m4 is one of the most reliable airsoft guns out there. There are gas blow backs,spring, and AEG's. They are sturdy some of them are 5-8 pounds (plastic) and the metal ones are about 8-11 pounds. I would purchase a full metal airsoft gun because they dont wear out as much as plastic do and the full metal airsoft guns live longer. we all can say you drop a plastic gun, who would know what will happen. I have purchase for my first gun a JG m4 s-system full metal for $250.00 best airsoft gun out there for beginers and when i was making more money at my summer job i but upgradable parts so i pushed the FPS to about 525 until i got the li-poly battery installed it went to about 550 FPS. I acctualy still have it with me right now. I had it for about 2 years now and no damage to it.