All bullet manufacturers make bullets for different applications. The Sierra Gameking is specifically designed for long range shooting with superior accuracy, they will almost always have a higher BC than most other hunting bullets of the same weight in a given caliber, it is not designed to be an everyday big game bullet. Sierra makes the Pro Hunter bullets specifically for more common hunting ranges. And I think Sierra deserves credit for offering the Gameking - a bullet that is so unique - though, perhaps they would do well to inform shooters of the exact criteria the bullet is designed for - Nosler and Woodleigh both list an optimal impact velocity range for their bullets.
I would carry a rifle loaded with ammunition that works at moderate ranges, and if a long shot presents itself, I can load up a Gameking, knowing that it is more accurate with less drop and wind drift than other bullets, and it's designed to expand very well at the lower velocities the bullet will be traveling at upon impact with the target at those long ranges. For a .325 WSM the minimum range I would shoot a Gameking would probably be 300 yards, the 220 grain bullet is still moving about 2200 fps at that range. Now take that exact same bullet and shoot it from an 8mm mauser (8X57), and it'll be running only 2000 fps at the muzzle! Say a hunter gets a 100 yard shot at a moose with that gun, the Gameking is probably the perfect bullet for that shot, the impact velocity will be low maybe 1800 fps at best, but the Gameking is made to still expand perfectly at 1800 fps - best bullet choice for that hunt. Whereas, if the hunter had chosen an A-Frame, at 1800 fps the bullet would not expand at all. The hunter has the responsibility of choosing the right bullet for the conditions of their particular hunt.
I am not a fan of the Nosler Partition at higher velocities either, they lose a lot of mass at very high impact velocity. I am very curious about the Barnes TSX bullets expansion, most reports say that they expand like they claim, but the expansion is not much larger than bullet diameter.
The Gameking is a specifically designed bullet. If you use it for the purpose in which it was designed for, it performs remarkably well. The Accubond performs very well at almost all velocities, and has become my choice for almost everything. But if I have a once in a lifetime shot at a sheep at 500 yards, the Gameking is made for that, and they are very accurate.
Without contacting Sierra directly about each different bullet, it's hard to say where they will perform best. Look at the difference in muzzle velocities for the 7mm calibers or the .30 calibers, or like I mentioned, the 8mm's. A 7X57 will have a MV of maybe 2400 fps with a 175 grain bullet, yet a 7mm RUM will push that same bullet at 3200 fps - that's an 800 fps difference in velocity! The MV difference from low to high in the .30 caliber rounds is probably even wider. And Sierra or any other manufacturer has no way of knowing which cartridge you might be loading their bullet into. What the reloader needs is for all bullets to be given an optimum impact velocity range ... should be marked right on every box, and this will probably occur more often in the future. This way, the loader can use a ballistic chart for their particular rifle, and determine at what distance their bullet will be traveling at the appropriate velocity to give proper expansion. A hunter could tailor their ammunition to changing hunting situations - purpose-built ammunition - one of the benefits of loading your own ammunition.
As for the original post, I would bet that all of those velocities would probably tear up a Gameking pretty badly, however if those are all muzzle velocities, I would say that a Gameking launched at those speeds would really be ideal once you got out past 300 yards or so.
