I would like to make an upper strickly for distance shooting.  I am debating on buying a Bull barrell kit from J&T or just assemblying an upper starting with a stripped upper.

What should I look for if I am trying to get the most accurate rifle possible?  

here are the kits from J&T I am looking at: jtdistributing.com/store/barreled_uppers_bull.html  does anyone have any experience with these?  would I be able to make one better for around the same price?  if so what parts?  I like the idea of building the upper so that I can spread the cost out a little bit.

thanks,
Seth