Just in @ Dlask Arms Corp. are 3 different lengths of AR-15 barrel. All are 4140 Cro-Mo steel with chrome lined bores and Phosphate coated. The 10.5" & 14.5" barrels are 1:7 and the 16.5" are 1:9. These are REAL, genuine M4 barrels made to the highest standards. There are only 10 or so of each length and can be found here on the site :
10.5"
http://dlaskarms.com/products/ar-15-10-5-cqb-barrel
14.5"
http://dlaskarms.com/products/ar-15-14-5-5-56-nato-chrom-lined-barrel
16.5"
http://dlaskarms.com/products/ar-15-barrel-16-5-m4-profile-chrome-lined
10.5"
http://dlaskarms.com/products/ar-15-10-5-cqb-barrel
14.5"
http://dlaskarms.com/products/ar-15-14-5-5-56-nato-chrom-lined-barrel
16.5"
http://dlaskarms.com/products/ar-15-barrel-16-5-m4-profile-chrome-lined