What is the timing on performing his free barrel roll?
Let's say he drops Cluster Mines directly on a ship. Does the detonation happen first? Or does the "after dropping a bomb..." part of his ability happen first, meaning he'd have to choose which way to barrel roll before knowing the results of the detonation?
If the mines go off first, and kill the target, that would certainly open the board for a barrel roll that perhaps wasn't a good option while the ship was still on the board.
The phrasing for proximity mines in the FAQ is that they immediately detonate, so I'd say it blows as soon as it hits a ship, then you barrel roll.
1. You take an Action to drop the mine, or simply drop the Bomb.
2. Resolve effect of the Bomb or mine.
3.Perform a free Barrel Roll.
if you have Advanced sensors you could do all this and then move, and if you combined this with Experimental Interface then you could potentially take a Boost or other action, then do steps 1 through 3. and if you chose a green manuver you would then clear the stress from EI, it's lots of fun 
Well you arent going to resolve effects of bombs until the end of the activation phase, but I agree with your assessment for mines and the net. I guess the key is the "immediately detonates" clause in the FAQ. Thanks
combined this with Experimental Interface then you could potentially take a Boost or other action, then do steps 1 through 3. and if you chose a green manuver you would then clear the stress from EI, it's lots of fun
You wouldn't be able to do much - if anything - with EI following the bomb-drop barrel roll.
You can't boost as EI restricts you to performing actions only from equipped upgrade cards with the Action header - boost is on your action bar so it's ruled out.
At present I'm pretty certain that the only upgrade cards with the action header that the Punisher can equip are the Connor Net, Prox Mine and Cluster Mine - and you can't drop more than one bomb, or perform the same action twice in a round.
***Edit*** sorry misread the post - ignore me