Did you know the muzzle velocity of a NERF dart out of a toy gun? Neither did [MJHanagan] until he did all sorts of measurement. And now we all know: between 35 and 40 miles per hour (around 60 km/h).

Nerf is no stranger to making blasters that can pack a little punch. Its Rival line fires foam balls out of the barrel at some 70 MPH and it's not nothing when you get beaned with one. But this DIY ...