To echo some of the ammo-related issues...
The VP9 has a stepped chamber, which is hell with Steel/Aluminum cased ammo, *some* reloads, and other non-SAAMI spec ammo. HK recommends only quality brass cased ammunition. After the ONE stuck case of Tula 9mm I had (out of around 200 rds that session, mind you), I was a little concernicus that my VP9 wasn't as reliable as my Glocks that eat steel cased ammo like its going out of style. However, after researching the whole stepped chamber thing, it isn't as huge a concern anymore. I only shoot brass through my VP9 (to include Federal American Eagle 124gr, Freedom Muntions Reman 115gr, Ultramax Reman 124gr, WWB 115gr, Fiocchi, 115gr CCI Blazer Brass 115gr, Speer Lawman 115gr, and Speer Gold Dot 124gr +P) and haven't had an issue since after thousands of rounds.