Interesting simulation findings from the fate combat simulator written in perl: https://gist.github.com/7780da3b19b7440f7e85
Against two mooks in a "fair" gunfight, the ability to take consequences to buy off stress keeps the probability of success pretty reasonable (player wins 43.42% of the time). Against three mooks, however, a "fair" gunfight is almost always a losing proposition for the player.
However, if the player has just an advantage of 1 in guns on skill, it gets a bit closer to an even match. Advantage past that seems to be overwhelming.
Player vs. 2 or 3 Mooks:
Pv2M Guns Skill diff 0:
Blue team dies: 56.58%
Red team dies: 43.42%
Average # of actions before death: 8.3381
Pv3M Guns Skill diff 0:
Blue team dies: 90.66%
Red team dies: 9.34%
Average # of actions before death: 8.0528
Pv3M Guns Skill diff 1:
Blue team dies: 57.63%
Red team dies: 42.37%
Average # of actions before death: 9.8014
Now, this is straight shooting, without any attempt to create advantages – different strategies might end up with slightly different odds, but there you have it.
Perl script for simulating fate core combat