Pretty sure they're somewhat to scale.
Honestly though I'm 5'7 myself and the M4 is a pretty good size for me and it doesn't feel like a "toy" in my hands.
Maybe it was you noticing the plastic and how light it was that made you think it was "too small". Handle a "real" airsoft M4 and see if you really like it. Either that or just go with the AK, there's nothing wrong with that and I'm even trying to get my hands on an AK to do a project on.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE