My first 7.62 AR platform was a Rock River brand. I still have it but as I've aged, I don't shoot it much. It is too heavy to reasonably hunt with unless in a blind or someplace where you don't have to carry it far. I have to use a padded shooting vest with a padded boot on the stock, especially in summer when it is hot and only a T-shirt to shoot it more than one 20 round mag. It is really a hard hitting rifle when compared to my AR 5.56. It is just suited for younger, more energetic types.
Reloading the 7.62 requires a lot of case lube when sizing compared to the 5.56.
At least surplus NATO rounds are, or use to be, available.
I still have it and have thought about getting rid of it but can't seem to bring myself to that point.