Very true...but I am a gun doc
(but I'm also slow and careful with everything, broken a few too many things in the past by trying to be quick.)
To the original post...
If the box says its a 300fps MP7 its probably a lie or chronying with .12's. The TM MP7 I owned shot a consistent 250fps and the Tactical Force MP7 I owned shot 260fps and it alone was quite high. I have never heard of an MP7 out of the box shooting 300fps.
My longest ranged AEG ever is my TM M14. It seems like no matter what it chronies it outranges everything else I have experience with. Even at 360fps it could outrange most 399fps guns. I have it set to semi only and its currently sitting around 415fps and can shoot further than any sniper rifle I have used including 500fps ones. I find hopup has more to do with range than anything else. Not just hopup settings but hopup type, how well the barrel sits, build quality, hopup rubber type, etc. Armalites tend to be mediocre at best, G36's are quite nice, and nothing I have seen can touch a TM M14 hopup.