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.
Tactical Force Mp7, box claim 300 FPS, I assume it is .12 gram, Xtreme tactics allow only .2 gram ball and it has to be from them (can't bring your own).
But I does change my mind when I hear good feedback about different guns such AUG.
my mind is stand on line b/w G36 and AUG.