If you want something to shoot bullseye go with the AR in either .223/5.56 or 308/7.62 or else the M1A.
HK is supposed to be real accurate, and you can use G-3 magazines at $5-10 each, BUT, the fluted chamber makes reloading a PITA, and if you ever need to replace the barrel the supply is very limited, because very few companies are set up to flute the chamber.
The AK is strictly a fighting/ hunting/ plinking carbine, neither the rifle or the cartridge are designed for one hole groups, you might get them, but it will be more due to you skill, and getting lucky than to the inherent accuracy of the gun and load which were designed to be "good enough".