If you are modeling this figure (or any other figure) as Standard / Typical UDF Solider you would be correct to use AK family weapon.
If you are modeling UDF Special Forces you would be wrong to use AK and would need to use AR / M-4 family or a Tavor.
If you are modeling a Ukrainian Territorial Guard / Militia you can use anything including an old Mosin Nagant w/ scope.
Additionally if you wanted a correct figure wearing Mollie Chest Mags, you need to use (at least some) Bungee Speed Mag Pouches because covered pouches are not that common anymore.