Too long didn't read version o nbottom.
automatic says
it can fire a burst of shots with a single pull of the trigger to attack all creatures in a line... When taking a full-attack action with an automatic weapon, the wielder can fire as many bursts in a round as he has attacks, provided he has enough charges to make all of the attacks...Each attack roll takes a -2 penalty, and its damage cannot be modified by precision damage or damage-increasing feats such as Vital Strike.
Dead shot
At 7th level, as a full-round action, the gunslinger can take careful aim and pool all of her attack potential into a single, deadly shot. When she does this, she shoots the firearm at a single target, but makes as many attack rolls as she can, based on her base attack bonus
so two ways of looking at it.
One says full attack one says full round. So you could say that they don't stack at all, due to being different actions (ala vital strike, cleave and such ruling)
but, you could also read (see note below as well), "i'm using dead shot as a full round action to take my full attack action" and allow it to apply.
Personally, I think as dead shot specifies all attacks at one person,and against one person, burst only allows up to your normal amount of attacks anyway. That it doesn't really matter nor have any reaction in the end. With Dead eye you only shoot once in actuality , its just super well aimed. so full auto doesn't do anything for it, as it's focusing on one target only.
Automatic says when full round attacking you only get as many burst attacks as you would normally have anyway. "When taking a full-attack action with an automatic weapon, the wielder can fire as many bursts in a round as he has attacks, provided he has enough charges to make all of the attacks."
Basically it turns your one attack into a line with a roll to hit, so dead eye still only targets one guy.. so it won't aim and won't full auto I think.
sidenote: interesting the full attack action specifies Vital strike interaction. Supports mine and a few others (non pfs) ruling that vital strike can just attach to other "actions that are attacking". In which case it'd be the same sorta thing, and the automatic just affects any full attack action.
TLDR:
Automatic makes your attack into an AOE that you roll to hit each person in the line; up to your normal amount of shots according to BAB etc. Dead eye allows yuou to focus and take one shot at one target up to BAB etc. So they both do different things and don't really interact to me. you could use full auto and Dead eye (I don't mind the combined actions) but it would just net you a wasted charge, due to dead eye restricting the attack in it's wording.
