If you're not using extra software to make that chainfire of yours, like a program that simplifies it you're pretty much clean. People would whine, but you're actually spending a tiny bit of your mental concentration to chainfire, be it by clicking like crazy or using weapon groups.
Now if you were using an extra program to easily chainfire perfectly then since it's a minor thing, would you be okay if someone was using software to aimbot since it's only slightly assisting them in not having to think where to place their mouse. They still have to turn, click the fire button when they think it'll actually hit (since we're not using hitscans) and do everything else manually.
Point of the story - as long as you're doing it with skills and not extra software that wasn't really approved you're clean.