Should mention that Lead Shot and Reassembled Clean Shot are the only GCDs that are guaranteed to be a gain inside Gauss Barrel. Split, Slug, Clean+ammo are generally going to be minor DPS losses inside GB, compared to GB-off with autoattacks.

Also want to emphasize that none of this matters until you're hitting high 90th percentile numbers. No amount of stance dancing makes up for losing uptime, losing Lead Shot ticks, losing oGCD casts, etc.