well
That's an AK, likely a custom build.
I've only seen a very few SKS rifles that will shoot under three inches at 100yds with any factory ammo and they were both Yugos.
I will fully admit there are one offs out there that will and you might have one, but they're few and far between.
My Yugo, now sold, used to like "Fusion 123gr FMJ'' and Winchester 120gr Split HP best when it came to factory non corrosive fodder and shot them just over 2moa, off the bench, if I did my part right.