UPDATE: With dogs on my yard right now I can produce 99.153% inbred pups.
Now, they might all be deformed, rank, maneating curs, but it can be done in the real world by yours truly. We are officially in "no man's land" as far as I know for selectively producing a game bred bloodline in the APBT fancy with this level of inbreeding. Being as the prospective parents of this mating are clean phenotypically, I would actually expect excellence in every way.