Combat shotgun is better, but considering effective range of both these shooting irons, you'll most probably end up face down before you see who shot at you. If you want a nifty aimed-shot weapon, get yourself a Rangemaster or AK-112, their range will help you to even the odds. And if you do bursts, then AK-112 also suits you fine. Also take notice, these guns are easily farmable along with matching ammo, just repair them time after time...