I've been shooting deer/yotes with a 12.5" 6.8 for years, puts them in the dirt. I've had a version of the 6.5g that ran and shot well just didn't use it much so sold that off.
If I were looking for an all around use AR15, it would be one of those. 6arc would be a close 3rd once it has been...
I agree, Grey Ghost Precision worked with them or has designers from Mega. Primary Arms sells Expo Arms, their forged receivers match the rich black Mega anodizing very well.
Hell of a deal here for a large frame gas gun, not sure how they shoot though. Using the website they come with stainless barrels, maybe 1-1.5moa. I'd want to know what length the gas system is also...
The Kidd should provide the most accuracy and closely match the balance of the oem bbl.
Not really apples to apples but I'm running a 10" feddersen on my steel challenge 10/22 with a Burris FF3, works great for that type of shooting.