FAST endos will have lower base accuracy. ACCURATE endos will compensate for the spread when stability isn't at full by a little bit. One thing I can suggest with the Sniper Cannon is staying grounded since you regenerate stability quicker and have stability damage resistance.
Try shooting from an elevated position, like buildings. Cars and tanks are relatively low-profile so a circular spread can end up missing if it goes too high or too low. Taking the high ground makes them bigger.
