The SIG 550-series is the Swiss battle rifle. It's built on the AK action, but only after Rolex worked on it. It's like the Rolls Royce of AKs. And it shoots 5.56mm NATO.
I don't know if anyone has developed match-grade ammo for the AK, but that would be a start.
A good investment, and one I have on my AK, is a plastic buffer pad at the end of the recoil spring guide. The AK and AKM are designed for fast, violent action to overcome rust, crud, and crappy ammo. But that tends to batter the weapon over time, causing cracks and rivet failures. Of course, the original weapon was intended for a short operational life time, to match that of the troop.