The lack of combat boost really limits this card, especially on hard or expert level. If the original Shotgun is also an option, it is usually better, as in comparison it gives +3 twice for only 2 resources more. The sawed-off is only better if you can succeed by 6, which is very difficult indeed for most enemies that you might want a big weapon to fight. For s without access to cards, all but perhaps the most buffed Tony Morgan would prefer Chicago Typewriter and .45 Thompson over the sawed-off, both also capable of dealing 12 damage but much more likely to do so.
Item. Weapon. Firearm. Illicit.
Uses (2 ammo).
Spend 1 ammo: Fight. Instead of its standard damage, this attack deals 1 damage for each point you succeed by (to a minimum of 1, to a maximum of 6). If you fail and would damage another investigator, this attack deals 1 damage for each point you fail by (to a minimum of 1, to a maximum of 6).
This is a really good target for your Three Aces success. If you are running a Three Aces Rogue deck anyway, and are also wanting to get in on some damage, I would recommend going for this as a combo piece to that.