The way archon damage works is just bizarre. I kind of get the idea that its better to do single larger hits than multiple smaller ones, but i have never seemed to make that work personally. I have certainly seen it done though - last archon battle had a player who consistently smacked 20 percent off the archon's health bar, to the point where the rest of us actually stopped attacking it and just let him get on with it. We figured that our attacks and presence probably made whatever he was doing worse, so we just left him to it and tried to draw fire and be somewhat useful that way.
Made a nice change from the usual spammy endless bullet sponge thing, but it was pretty clear that nobody had any idea quite what that guys secret was.