Another recommendation for JBM. It's my go-to ballistics calculator.
Actually, JBM has a number of different interesting calculators on his website. From the link that Cyanide gave you, you can choose "Trajectory", or "Trajectory-- Simplified" (that latter has fewer of the bells and whistles but is still plenty powerful, it's usually the one I use).
JBM has a check-box that allows you to select yards or metres.
In any ballisitics program, if it only supports yards, tell it that you have a "110 yard zero" (i.e 100 metres), and that you want it to display data in increments of 110 yards (ie. increments of 100 metres ;-).
One nice thing about JBM is that it allows you to select a number of common bullets from its bullet library, in addition to doing it the old fashioned way of entering a weight and BC. And as luck would have it, it has an entry for "Hornady .224 cal 75 gr Amax", which has the bullet data from Hornday.
Even better, it has an entry for "Hornady .224 cal 75 gr Amax (Litz)", which is much better, real-world test data done fairly recently by Bryan Litz for some of the more common target shooting bullets. I would highly recommend using the "(Litz)" entries whenever one is available.
So entering in the following data (or ticking the relevant boxes):
* Library: bullet = "Hornady .224 cal 75 gr Amax (Litz)"
* Muzzle velocity = 2950 ft/s
* (leave default values for 1.5" sight height, 10mph crosswind at 90 deg, etc).
* Minimum range = 0, Max range = 900, range increment = 100, zero range = 300
* (leave default atmospheric conditions 59F, 29.92"Hg pressure, 0.0 humdity - this is "standard atmosphere", which is usually a bit more demanding that commonly shot in conditions)
* keep "Column 1 units" as 1.00 inches, and "Column 2 units" as 1.00 MOA.
* check off "elevation correction for zero range" (this references your bullet rise/drop to your 300m zero that you requested)
* check off "ranges in meters"
When I run this, I see that the 300m drop in MOA is 0.0 (i.e. that's your zero), and the 900m drop is -28.5 MOA. This suggests that you won't have quite enough elevation, even if you do everything absolutely perfectly.
(now having said that, there are a number of ways to cope with that and successfully shoot your rifle at 900m anyway, but that's probably worthy of another thread in itself).
