Built an MP7. Here's a size comparison with my winchester rifile.
Here's a pic of the refined model.
Stock and foregrip extended.
Ammunition: 7.6x13.3mm papermate erasermate pen cartridges (non-compatible with other rounds)
Capacity: 11 rounds
Barrel length: 17cm
Length: 39cm, 41cm overall,57.5cm with extended stock
more details: http://www.mocpages.com/moc.php/25562