An M4 is a short barreled version of the M16, so yes, they can look quite similar.
The M4 CARBINE IS BETTER THAN THE M16.
Most airsoft battles take place in close quarters which is what the m4 was made for. Unlike the m16 which was made for longer ranges
It depends on which companies make the m4 you have, but generally companies stick to the same dimentions for magazines for the m4/m16 family.
No
it seems like no one knows.
Most airsoft guns have the motors in the grip (like AK, M4/M16, and G36 models) but some guns (mainly bulpups) have the motors entering the gearbox from the back.
The best airsoft gun you could get for $150 would probably be an Aftermath gun, but you could get a JG M4 or M16 for under $150
go with trusted brands like, DBoys, JG, CA, AND TM
I highly recommend the M4 or the M16. They have great accuracy, and they don't jam. Also, the HK416 is a good choice.
its m16 as number 16 like m60 m4 m15911 etc
AK47s or really any other variant costs pretty much the same as an M4/M16. Although I don't really know how you can buy any decent gun for 55 quid.
get a well m4 or m16 off of airsplat.com but you could get better ones for not much more off airsoftgi.com