Silent Manufacturing is a full service machine shop and we offer barrel threading on practically any gun. Contact us with what you want done and we can work you up a quote.
Our standard service is $135 and includes a custom fit thread protector. Gun must be stripped of all accessories and optics before bringing it in. Surcharges will apply if we have to remove accessories.
Visit http://www.silentmanufacturing.com/barrel-threading/ to go to our website to see more pictures.
We aren't the cheapest around for this service, but if you think a good gunsmith is expensive, you should hire a cheap one!