7.62x39 can do the trick, it's my preferred round. If you're curious about potential of bulk 7.62x39 watch the ak operators union shooting the vepr at 500 yards. They got 1.34moa at 500 with wolf 123 fmj.
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500m is doable if there is a laser range finder, a ballistic calculator and it is aimed at the sky to deal with a drop that is more than double of 5.56. In practicality, the rainbow trajectory is not useful other than range shooting for amusement.
Out of an AK, it is really a practically shootable cartridge out to 230m'ish. After that it pummels like a rock.
What would be a better round for someone new to the sport for cost and accuracy