Originally Posted by thpethalK
Or, get a gas rifle...no gearbox, metal receiver, metal rail
But then mags will cost a fortune. For a beginner, I don't think that would be economical.
Personally, I would buy the rifle with the metal receiver, and then buy aftermarket rails, because A) It's much, much easier and cheaper to buy and install rails than it is for receivers, and B) there is (arguably) much more choice in handguards (such as tube-style, free-float, RIS/RAS, etc.) than there is in receivers. I'm not saying there is no variation in receivers, but there is less so, and the difference is often unnoticeable.