Let's change the question a bit.
Are the shot's I'd take with my 7mm STW that I wouldn't take with a .243 win. Yes there are.
The higher velocity and better ballistic coefficient of the 7mm STW flatten the trajectory and improve wind performance. This reduces the circle of error probability. Consequently this will shooting conditions that would be unacceptable for a .243 Win acceptable for the 7mm STW.
Additionally, providing you hit the target, the bullet must retain the ability to do sufficient work to secure the game, especially at distance. At 1000 yards the STW gives full penetration on an antelope, I'm not sure the same could be said for the .243 Win.
Throw in the quartering shots and Texas headshots at distance and it becomes very apparent why there are plenty of shots I'd attempt with my 7mm STW that I wouldn't even consider with my 6x45.
For all you easterners who hunt from stand, or over bait, and never shoot past 100 yards, fine, for you guys it might not matter. Out here in the west in places where a "close shot" is 300 yards, its' wise to bring enough gun.
