I have decided to do a basic comparison/competition with a couple of my rifles, and I wanted to get input as how to do it fairly and in an unbiased manner.  Here are the rifles:

-Rock River M4gery w/ Aimpoint CompC and 6-position stock (2 stage NM trigger)
-Bastard M4 clone (DPMS lower w/ 6-pos stock and Oly Arms M4 upper) w/ EOTech 511
-Bushmaster CAR-15 w/ ATN Digital Ultra sight and A2 stock (2 stage NM trigger)

I mainly want to test the optics, but might as well test the uppers as well (since the three are all different).  What would be good tests for the optics and uppers?  I'm not interested in reliability, and I won't be dragging the guns through the mud. I can shoot out to about 250 meters, and I have plenty of ammo to run the comparisons with.  Oh, ammo will be polymer coated Wolf 62gr.

Any suggestions?

Use the same target, same distance, for each setup.  Try different distances each time you test.  I.E., 50m, 100m, 150m... so on.  See which does better for distance.  Try firing slow, taking your time and making precision shots to the best of your eyes (and optics) ability.  Try firing at a faster pace, see how the optic is effected by faster paced shooting.  You already stated you're using the same ammo.  Good.  

If you can try setting up multiple targets for fast target acquisition testing.  

You could do all sorts of things.  Try using the optic in different positions if you can.  Shoot prone, shoot knelt down, shoot standing.  Shoot in different weather conditions.  See how each optic performs in the rain, in the cold or hot weather.

Whatever you do just make sure things are the same on each EXCEPT for the upper and optics.  Don't change anything else.  Those are the variables of your experiment, all else must remain as constants.

Nikkels.