The following chart shows the bonus you get from bringing cannon to a siege. You can never have more than a +3 bonus from cannon, I tried using over 10,000 guns on a minimal fort and it was still at +3. However, this bonus is independent of any other bonuses from leaders or dp settings.
Code:
Fort size Fort
Guns 1 2 3 4 5 6 Size Name
0 0 0 0 0 0 0 1 Minimal
10 1 0 0 0 0 0 2 Small
20 1 1 0 0 0 0 3 Medium
30 2 1 1 0 0 0 4 Large
40 3 1 1 1 0 0 5 Mighty
50 3 2 1 1 1 0 6 Maximum
60 3 2 1 1 1 1
70 3 2 1 1 1 1
80 3 3 2 1 1 1
90 3 3 2 1 1 1
100 3 3 2 2 1 1
110 3 3 2 2 1 1
120 3 3 3 2 1 1
130 3 3 3 2 2 1
140 3 3 3 2 2 1
150 3 3 3 2 2 2
160 3 3 3 3 2 2
170 3 3 3 3 2 2
180 3 3 3 3 2 2
190 3 3 3 3 2 2
200 3 3 3 3 3 2
210 3 3 3 3 3 2
220 3 3 3 3 3 2
230 3 3 3 3 3 2
240 3 3 3 3 3 3
- 1