So I'm itching to build another AR, but this time I want something I can do some distance shooting with. Not too far, maybe 500-600 yards with a .223. Anyway, at first I was thinking of building an upper, but then I was on Rock River Arms site and seen they have some uppers that are basically what I am looking for. One that really caught my eye was the Predator Pursuid Rifle Length. While I was looking at it I noticed that it is cryogenically treated. I was just wondering if anyone has a cryogenically treated barrel, either purchashed that way or sent off to get treated. What are your experiences, good and bad? Is it worth it? I've seen statements that it increased accuracy, but I also found a statement made by Armalite stating that it is not worth it.