Well.... the only way they would actually be "accurate" is if you had the exact same paint/bore match..... Each batch of paint is different and maybe thats why your other barrels didnt work? I dunno... Im kinda confused at what you are trying to say... But I have the one piece and love it... great barrel... all 16" of it.... I also use B.E paint!
If you are totally conserned about getting the right bore/paint match get the freak barrel system so you can match it whenever no matter what type of paint you have...