All I know is that some of the called shots, specifically Bulls-eye Double tap/burst is going to need errata. It's clearly OP and not enough of a penalty is being taken with that Ammo Called Shot. Ares Alpha with APDS is -6 AP. So a Bullseye Burst called shot is base AP x number of bullets fire with a cap at 3. -18 AP pretty much means everything is getting mowed down.
I'm actually looking forward to picking up the AA-16 full-auto shotgun. Combining that with Small Unit Tactics skills, teamwork plays and suppression fire will prove vital for a lot of CQC involved missions.