check out the Burris AR-332. it gives you decent "BDC" out to 500 yards, red ring with crosshairs, green ring with crosshairs and if your batteries go dead, you still have a black ring with crosshairs. it comes with mounts, lens caps and "never lose" adjustment covers. all for $319.
I run irons on all my guns rarely use optics. I'll tell you what shooting 200 yards without optics or high tech gadgets just you and your rifle it just gives you a warm fuzzy feeling
i just noticed the up to 400 part. look at the vortex viper hs 2.5-10x44. price is 350-360 depending on the reticle you choice. they are great optics. if you want to see them im person and are at the 1500 stop by my table ill have a few up there with me