I haven't even seen them in stock anywhere, yet.
Though, I have a suspicion that they may be versions of the Midway Dogtown, finally labeled under the manufacturer's own name. (I have no data to back up that "hunch"; just experience with Nosler products, the Dogtown bullets, the packaging methods for both, and Nosler's habit of partnering with other vendors and manufacturers for bullet designs.)
If they are... Nosler's velocity claims probably won't hold up. (They claim there is no reasonable velocity limit for these bullets.) The Dogtowns had the same claim, when they first hit the market. Within a year, they had a 4,000 fps max velocity listed. (With a recommendation for 3,800 fps or less.) As a .220 Swift shooter, with a supply of 34 gr Dogtowns on hand... I was less than impressed with bullets vaporizing. (I was an "earlier adopter".
)
If they hit the market at a reasonable price, I might give the 6mm 55 gr Spitzer a try in my 6mm wildcat. How fast can they go?