Random factor

[Barca]

Hello all,
Is there any random factor involved in combat resolution (melee and fire)?

Unless I miss some modificators (there are a lot for melee and I find them very good. However, I think that there are not enough mods for ranged fire: distance, fired from shieldless side and/or rear for example are lacking in my opinion) the results in game are not what they should be (f I read correctly the missile or melee effectiveness charts), though not far from them.