I have never used Double Action much myself and thus I am not quite sure how these two rules interact: DA states that it reduces Burst to 1. The fireteam burst bonus adds +1 to burst. Under the fireteam rules is also stated that: "In the Reactive Turn, this +1 Burst bonus is not stackable with other bonuses or Burst MODs provided by other rules, Special Skills, Equipment, or Hacking Programs, except for those who specifically state otherwise." I would assume that the burst is therefore 1, but I am uncertain as I have been told it is B2. Which one is it and why?
It's B2. You start at B1, and the Fireteam adds the +1B, so your DA ammo would be at B2, much the same way an ML in a Fireteam is on B2 in ARO.
DA ammo by itself doesn't have a burst modifier. You're looking at some specific weapon, like a Multi Rifle, or something. The weapon says you get B1 when firing DA (in your particular example). This isn't a mod, this just is what the Burst is. Your Fireteam can now add a +1 Burst bonus to that weapon. Burst 2 Double Action!
Anti-materiel Mode. DA Special Ammunition. Using this Fire Mode, the shooter fires DA Special Ammunition. The Burst value of the weapon is reduced to 1. This Mode possesses the Anti-materiel Trait. Sorry, an "Alternative mode". It is still a unique profile however
