We live in a 5.56x45mm/.223Remington and 7.62x51mm/.308Winchester dominated world. Why? Because ammunition for them is the most available, and therefore usually the more affordable option.
Does that mean those are the best option? Of course not. However, because they are popular, the majority of optics out there are designed around them when it comes of justified applications of violence or pre-calculated competition use. But there is another way...
Low Power Variable Optics (LPVO) with true 1x (No Magnification) capability have opened up the Carbine and Battle Rifle platforms to a level of flexibility that no one can look down their nose at.
Want to take a 12.5 inch AR15 to 800 yards without having to aim above the skyline? 6.5 Grendel and .224 Valkyrie are an amazing option. What about dropping wild pigs with minimal noise or light signature? .300 AAC Blackout has more options than you can imagine. Dangerous game hunting? 350 Legend, .458 SOCOM, and .450 Bushmaster are all going to hit like a freight train compared to 5.56.
What options are there for the bigger brother of the AR15? How about a lighter, faster, and more flexible use for your AR10 sized battle/hunting rifle? Go from dense woods at 1x to 300+ yard shots with the spin of a ring. Worried that 6/8/10X won't be enough magnification? Try it before getting concerned. You may find yourself surprised at what an 8x optic can reach.
The wide embrace of the LPVOs for all kinds of roles has taken Armalite platform rifles into the next age. Not to mention all their competition in the Carbine or Battle Rifle world.
Think an LPVO may be a good option for you carbine? You're probably right...