UBC is fully cured after 5 initial rounds. There will always be some fouling during the curing shots because it takes a few shots to heat-press the UBC into the little imperfections in the bore. If you shoot more than 5 rounds it isn't cured any better, and the fouling picked up during the first 5 shots will attract more fouling.
Also, some bores will take more than one application for the stuff to reach maximum effectiveness, especially larger bores. I had to apply it twice to a .338, for instance. If you decide to apply it again, only clean rthe bore with solvents and nylon brushes, no abrasives or brass brushes. Otherwise you'll be "uninstalling" the UBC, to use computer talk. But in bores up to .30 one application usually does the trick.
