mjkten,
Not to overwhelm you with too much data, but for the Known Distance (KD) portion of your IBC, don't forget the standard come- ups we teach at every AS. If you are zeroed in at 100 yards with your AR15 when you arrive, then you have all the data you need to transition to the 25 yard line. The two important things to remember are that for your AR15, the 25 yard zero and 300 yard zero are approximately equal, and the standard come-ups tell you that to compensate for the bullet drop that occurs between 100 and 300 yards you need to put in a 4 MOA correction, (100>200 is 2 MOA, and 200>300 is 2 more MOA).
If you were bringing a .30 caliber rifle, then your 25 yard zero and 200 yard zero would be about equal, and the standard come-ups would be 2 and 3, (5 total).
So, put that all together and you realize that if you start with an AR15 with a good 100 yard zero, you can put in a 4 MOA correction to derive a 300 yard zero, (raise the rear sight to raise the POI), and you will be darn close to being spot on at 25 yards. That is exactly what I did when I attended a KD event last summer with two rifles both zeroed at 100 yards and it worked like a champ. It also really illustrates that the theory in the KD section of the AS manual really works.
Have fun at the IBC!
JL