As a tried and true member of the 10mm club I will state that most of the off the shelf ammo is neutered and barely more than the 40S&W. Most of the off the shelf ammo is close to published data in my experience. That said, there is some ammo that is truely what they claim and then some. Double Tap Ammo.. http://www.doubletapammo.com/php/cat...hp?cPath=21_25
Of course you can always reload to those levels.

I have had no trouble replicating published data with Double Tap ammo through my chrono from a Gen 2 G20. Second closest velocity is Hornady.