Not a huge difference other than a slight strength increase to handle the .308 recoil better.
The SR-25 mount will engage 4 lugs of the 1913 Picatiny Rail... I believe its 4,, it will engage additional lugs over the AR-15 mount for addition recoil tolerance without moving the SR-25 mount has been discontinued, so the AR-15 mount will have to do unless you can find one used somewhere,, lol...