Ok, I agree that I probably wouldn't see any modern sporting rifles on whatever fictional battlefield we are talking about. But the question remains, what is it about a battle rifle that makes it more acceptable in a combat situation?
At least three attributes:
1. Functions after extreme physical abuse
2. Functions when wet, frozen, dirty, etc.
3. Functions after high volume of fire
4. Easily field serviced with minimal tools
5. Interchangeable parts require no fitting
There are issues of accuracy and ballistic effectiveness as well.
Many of the rifles mentioned above are sniper weapons. These are a special case, not general issue battlefield weapons. The fact that the Rem 700 action works well for snipers does not make it suitable for general issue. It's an excellent rifle, but not for the battlefield. The M70 might be better for that use, since the extractor, ejector and trigger mechanisms are all simpler, easier to service and more robust.
Compare the 1911 to a 3rd Gen S&W autoloader. The S&W is a great pistol, but it has lots of small parts that can break and are a b*tch to service. You can take a 1911 almost entirely apart with little more than a screwdriver to remove the grips.
There's a lot more to battlefield weapons than going bang, or even going bang accurately.