The original M24 had an effective range of about 800m. The new, upgraded M24 hurls heavier .300 Winchester Magnum rounds over a kilometre away. All while being more silent and accurate. Note to enemies: You are so dead.
The fancier scope has an adjustable magnification system, ranging from 16.5x to 25x, while the new body design is modifiable in a way the old one wasn't, allowing attachments like night-vision accessories. It's more awesome in every way, at least on paper.
The reason the military's pursuing a $US5.6 million upgrade of the venerable sniper rifle, BTW, is that it's more valuable than ever in the combat environments of Iraq and particularly Afghanistan, where sniper engagement is super serious.