It caps at 20, as I recall, and it's difficult to maintain that chain solo depending on enemy counts, your hit rate, etc. I favored doing bats in Woh Gates on my mythic DRG, and I could maintain chains of up to 37-38 at best; one Stardiver that didn't hit its full potency or a delay in engaging due to wiping out the bat population and waiting on respawns usually breaks it. That being said, the chain bonuses are quite noticeable; before I finished RoV (+100% CP, not sure where it applies however) and before this campaign, Trizek Ring on bats would get me something in the ballpark of 4500-5000 at Chain 20, where the bonuses seem to cap. During this event I was seeing closer to 11-13k per kill... for the three or four kills that my Trizek Ring lasted! :P my Capacity Ring lasted a lot longer and I was still getting solid 6-6.5k awards around chain 13-20.