20" barrel and you can only site at 25 yards??
2" high might not be enough to be honest. I don't really know what a round coming out of that barrel is going to be doing at 25 yards mathmetically, but I know it is on the way UP.
At 200 yards? I have read, depending on your muzzle velocity, that 200 yards is the "even" point of the round. Meaning that is neither + of - in elevation.
It's math that needs more inputs I believe. Or an MIT student.
Sorry, no definitive answer for you...