The Scout Rifle concept isn’t a hard set of Rules that Define a Scout Rifle as a Scout. They are really just guidelines that are flexible to fit within your needs, not someone else’s definition of what your needs are.
I had dinner with Jeff Cooper many moons ago. We talked for a good while about the Scout Rifle as a Concept and about the Steyr Scout specifically. He truly loved the concept… but not so much the Steyr product that bore it’s name at the time. He indicated that it captured the concept for the most part, but was not perfect.
For example… .308. Jeff Cooper himself, who made up the concept only used .308 as an example. He did not say that it HAS to be .308. Evidence to support my assertion, he was also fond of the .376 Steyr cartridge and shot his .376 Scout rifle quite a bit. He also had a .358 Lion Scout concept, which turned into the .376, which he called his Scout Dragoon. All were following the Scout Concept, not a hard set of rules.
The main concept of the caliber for a scout is that it’s a cartridge potent enough for your area of operation, and in a common caliber so ammo availability isn’t an issue. .308 Win is a great option, but not the only option. .30-30, .307 Win, 7.62x39mm… .300 BLK, and yes, even 5.56mm… pretty much any cartridge you can get your hands on that serves for 95% of your likely targets is going to work just fine for YOUR SCOUT.
The Forward Mounted Optic is also not a Requirement, but a configuration that Jeff Cooper found to work well with his Scout Concept. But many Scouts can use a normal configuration of scope, Red Dot, or other Optical Gunsight.
What the Scout boils down to is a light, handy, jack of all trades rifle that can do most of the practical things you might need a rifle for out in the field. A General Purpose Rifle, rather than something specialized. But “General Purpose” sounds Generic and unappealing.
In my opinion, the best Scout rifles I’ve seen are actually .30-30 Lever Actions… what are called “Lever Scouts”. They fit Cooper’s Philosophy of Use just about perfectly. They are light, thin, handy, and potent enough. They have a reasonable capacity, reasonably accurate, and always have and always will embody the Scout concept – arguably more than some Scout rifles which are too bulky and heavy for the intended purpose. In fact… Take any Marlin Lever Action in .30-30 and put a decent Sling on it… and your done. You have your Scout.
Lever Scouts > Bolt Scout.