The 10.1" LW barrel is part # 2300-002The 20" LW barrel (Challenger) is part # CH2009-14 but it costs $93The 14.6" LW barrel (from the custom shop) is about 50 bucks but you can't buy it unless you've bought a custom shop gun...Like I said, options are limited. They are 7/16" +/- o.d. mostly minus...Wyo
Out of the UK we have access to the EXCELLENT German HW barrel blanks via SILCO : http://silco.co.uk/categories/WEIHRAUCH-BARREL-BLANKS/