Most shooters argue the merits of their gun over another.
If your life is to depend on your weapon,as long as it fires a sufficent caliber to stop a man,is reliable without fail,then the rest is up to the gunner get to know your weapon,love your weapon,keep it clean,lubed,and practise,practise,practise.
Shoot at close quarters.Shoot at medium range.Shoot at long range.Shoot from weakside.Shoot standing,kneeling,sitting,prone,from under cover,over cover,around cover.
Having played woods paint ball I do know there is rarely a perfect shot,always something in your way.
If your area of ops include wooded or semi wooded areas dig and camoflague hidey holes,spider holes,whatever you want to call em measure off ranges and shoot from em.
Years ago when 45-70 was the round,old time marksman shot at ranges today being shot only with high powered magnum rounds,it is the shooter as much as anything.
If they could hit targets at almost 1000yds with iron sights and a round whose trajectory looked like a rainbow with modern flat shooting rounds all we need is massive amounts of practise.