I'm shooting a Trijicon Accupoint 1-4x on my carbine right now. I carry it on 1x/100m zero and that works pretty good out to 200 or so, then dial it up 4x/300m zero and that covers me pretty well to 500. It's got some nice features-
- You can slip the scales/zero without tools.
- It has graduated turrets for easy dialing.
- You can run the turrets covered or uncovered for easy dialing.
- It's pretty damn close to true 1x, so you can shoot it both eyes open.
- It has the same tritium/fiber optic illumination system as the ACOG.
I got it from Larue for abou 850 with the mount. Not too bad, but not cheap either.