bought this as a 17L barrel. a machinist buddy cut and threaded it with a single point threading so it very concentric and accurate. threads are cut 1/2 x 28, not metric.
the threads are not perfect but i will gladly refund money and shipping costs if you aren't happy with it a 3 day inspection period.
$85 shipped, postal MO only. thanks. IM's are best. emails get trapped too much.