Overwatch with many AP

[Terrarius]

So how exactly does it work when there is a big enemy walking into a high AP overwatch cone?
How many times does he get shot at?
It seems like(though this is hard to test): when interrupted the enemy steps back, and is shot at again. Than it steps back again, which repeats until the enemy has been pushed out of the cone or the overwatcher ran out of AP.
So if you get unlucky, you get only 2 shots

[sirhawkeye]

you described it correctly: any target that enters the OW cone gets shot at "immediately" as long as there is an AP left of the overwatcher. If it gets interrupted and thrown back, this move (most of the times) triggers another OW shot. If the enemy unit continues its turn with another AP of its own walking into the cone again, it gets shot again.

Anyways, OW isn't necessarily there to dish out maximum damage to one unit, but it helps you control and defend areas and deny entry to enemy units, intentionally pushing back a whole pod. If you make use of several units overwatching, you can easily defend zones from different sides, or concentrate on one spot to deny entry of several units following each other. For that you can set up your cones overlapping (thus maximizing the damage for the first unit entering) or in a way that one is the first doorkeeper (could be the one with most AP, depending on damage distribution) and the other OW cones are staggered behind to secure the entry zone when the first OW runs out of AP.

Another possibility is to put the cone over an enemy already in the vicinity, so it is tactically hindered to move/attack (or if so, is at least debuffed), and maximizes the number of shots from the overwatcher if he has more AP left than he would use for attacks in your turn.