"building", That's where it gets silly, attaching a vertical grip to an H&K with a light rail is like what, a 2 minute job with an allen wrench?
It gets sillier if you consider the vertical grip I was looking at has a thumbscrew on the end for tightening. Look ma' no tools!
I think that grip will just have to stay on the AR then. They'll just have to take my word that it's never been on the pistol, because there's no way I could prove where the grip has been, unfortunately. So if they want to lock me up they can whereever the grip is, because the vertical grip on my AR gives me the means to make a super-deadly Class 2000 mass-extermination device out of a .22 pistol.
*angry*