A bit of information for modders :
Since TU% costs are rounded down, you can have cases where a soldier can shoot less often when combat experience gives him one more TU.
Ex with the vanilla pistol :
18% of 55 TU -> 9 TU per shot, 6 shots, 1 TU remaining
18% of 56 TU -> 10 TU per shot, 5 shots, 6 TU remaining
I made the math, here are the TU % that produce this oddity :
1 to 9 : avoid, very inconsistent numbers
10 to 18 : avoid, inconsistent numbers
19,20 : 5 shots /turn
21 : inconsistent 5/6
22-25 : 4 shots per turn
26 : inconsistent 3/4
27-33 : 3 shots/turn
34, 35 : inconsistent 2/3
36-50 : 2 shots/turn
51 : inconsistent 1/2
52-100 : 1 shot/turn