Need help identifying this brass found on the range Sunday

The headstamp is: 5.7 x 28 06 & either FMB or FNB or FWB. A bit difficult to make out the last.

It's obviously a 22 cal. One member said that it was and H&K pistol round. I have no idea. I've never seen or heard of one before.

Any help would be appreciated.

Thanks

Roy Allain

Acctually, it belongs to the Five-seveN family of guns from FNH (Fabrique Nationaile Herstal). They include the P90, PS90, and the Five-seveN pistol. 2100 fps from a pistol.

http://img174.imageshack.us/img174/9760/img0208el9.jpg