I would consider a scout mount, probably the Ultimak since it is the lowest you can get. A red dot like an Aimpoint would do you just fine if you're only shooting out to 300 (and you can get a co-witness with one on an Ultimak rail), but if you feel like you need magnification, a 2.5x or 4x scout scope would work great too. The scout mount is nice because you can get the optic low enough that you can get by without adding a cheek riser.
If you want a receiver mount, consider ARMS, Sadlak, and Basset. Personally I prefer the ARMS because I like to take the optics off and shoot with irons a lot, and the ARMS is so low that it doesn't get in the way of the iron sight picture at all. The other mounts have a little window you look through for your irons, and don't work if you adjust elevation up for the longer ranges. If you put anything on a receiver mount, be prepared to figure out some sort of cheek riser to get cheek weld.