So if you have RB, then you are already maxed out in range? Might as well use smart drift control for the + 20 stability, or do I need the +1 impact from field choke?
You always want max impact if you're looking for a one hit kill/overkill in PvP. It is the max range + max impact that makes Felwinters/Matador/Party Crasher so desirable in PvP. As such, stability is not going to matter at all. For PvP, I would choose impact over stability when we're talking shotguns.