He will get that result only if he is extremely lucky.
Depending on the bullet used, the 243 has quite a range of possible muzzle velocities and ballistic coefficients, so it's pretty hard to say. And 1/4" at 25 yards translates to a big change in where you get your second crossover. Using the RSI Shooting Lab, 100 grain bullets, and 2950 FPS a 25 yard first crossover gets you about a 250 yard second crossover.
I'd just suggest to him that he test his idea before he goes hunting. Hard to argue with a group several inches from where you believe it should be.
