I've owned 10MMs since the early Bren Ten days. I'm glad to hear that a major American manufacturer is adding an actual full power, or nearly so, 10MM load. Btw, I chronograped a fair amount of 10MM over the years, to include the Old Norma, Cor Bon, Buffalo Bore, Winchester, Remington, handloads, etc. The old Norma 200 grain did do 1200 fps, or a little more, in all but one of my 5" guns. The Norma 170 grain ran around 1300. Cor-Bon 135 grain, advertised at 1450 fps at the time, averaged 1475 fps in the 5" auto, and 1485 fps in a 5" revolver. The Buffalo Bore 180 grain averaged 1320+, samples from a second box later averaged 1350+ in a 5" auto. I don't know if the lot numbers were different. I chronographed some Buffalo Bore .357 180 grain in 4," 5" and 5.5" revolvers. One 4"=1384 fps, another 4"=1430 fps, 5"=1436 fps and the 5.5"= 1514 fps!!! Without a doubt, other's guns,even by the same manufactuerers, and with the same barrel lengths as my guns, would produce different velocities, by a little or a lot. I think the Buffalo Bore ammo is certainly in the ballpark with their advertised velocities...ymmv