There seems to be fairly wide-ranging agreement that the Springfield "Scout-Squad" rifle is pretty darned nice as an all-around weapon.  My question is, with the forward-mounted rail as a sight base, are there any practical limitations on what kinds of optics that can be used?  I'm thinking about getting one, and I'm 95% sure I won't know what kind of scope / optic to put on it before I pick it up, and 100% sure I won't have the money to get it even if I do know what I want!  I'd just like to know what my limitations are, if any...

The most frequent use will be for deer / medium-sized game hunting, with a secondary purpose of being able to "reach out and touch someone" beyond the range of my 5.56N m4gery.  My goal is to be able to accurately hit whatever I'm aiming at out to at least 300 meters, preferably beyond.  Basically, I want to ensure that I am the limiting factor in taking a deer cleanly out to at least 300 meters, not the gun or my choice of optics...

Thanks for any & all input!