Hmm...haven't really heard much about the King Arm's bucking...they seem to make everything else good, so I can't see why there bucking would be bad...
As for the tightbore barrel...depends on what came in it I guess...I know the older ones use to come with madbull 6.03's and I would guess that the new ones come with ASGI's in house brand tightbore barrel which would translate to decent quality, but not really. It's more like a half ass tightbore and stock barrel mixed together. So just pull the barrel and hop-up unit it out...if its black, it's a madbull black python barrel...thats good...if its silver and very light weight, and made out of aluminum its just a stock G&G combat machine barrel, if its silver but made out of a heavier metal more like stainless steel, its probably an ASGI tightbore.