I posted this in the "HK Clone Talk" section:
I finally got mine, MP5 A5 22LR, to the range yesterday. I had installed a "Leapers UTG New Generation Bi-Directional Stanag Claw Picatinny-Style Rail H&K Matte" I bought from Midway. The mount required a little Dremel work to make it fit square and tight. I put an inexpensive TruGlo dual color open red/green dot sight. It was an indoor range, so I couldn't shoot long distances, but it was a real hoot. A couple minor adjustment to the sight, then just a matter of standing there and plinkin' out the center of the target. I am very happy with the way mine operated. Maybe someday I'll be able to afford one in 9mm.
Took it to the range again today, I absolutely love this little rifle. Yeah, I'm a wannabe.