Opinions vary, but Jeff Cooper had an idea of the general attributes of what a scout rifle 'should' be, not necessarily a list of exact requirements. Basically is is an all purpose rifle that could be used for hunting and self defense when needed. If you could have only one gun, it would be a scout rifle.
In a nutshell:
Bolt action (more reliable, less maintenance)
.308 or higher caliber (to take down targets up to 300lbs. at up to 450 yards)
Bi-pod (stability for longer range)
Forward mounted scope with long eye relief (for quick target acquisition while keeping both eyes open, which is important to maintain peripheral vision)
Iron sites (for backup)
Simple sling (for carrying)
Fixed magnification scope (1 to 2.5x)
The three modern scout models that come to mind are:
Steyr Scout: http://www.steyrarms.com/products/hunting-rifles/scout/
Ruger Gunsite Scout: http://www.ruger.com/products/gunsiteScoutRifle/models.html
Springfield M1A Scout Squad: http://www.springfield-armory.com/products/m1a-scout-squad/
I recently bought a Ruger Gunsite Scout (Lefty in 18" Stainless Steel Barrel). Great gun, waiting for my optics to come in the mail. Only negative is the 500 cycles you have to do with bolt to smooth out the action....but all you need to do is get some oil, turn on Top Shot and go to town.
