S-70 vs BL9 or any of the IS series guns

ARGO: I have tried most of the IS series guns and am currently working on the fabled S-70 130mm cannon "Finger of God" and I started thinking about how many times I have been down this road with guns. So far the BL9 gun is not what I would call a fantastic gun "It does do great damamge" but it also misses A LOT even close up and comming from a guy who has well over 20+ sniper awards I can tell you I have a lot better luck hitting targets with the D-25 cannon than the BL9. So with that said, Now I am wondering if the S-70 is going to be just a waste of time or will it possibly be a real gamechanger as far as cannons go?