I am going to purchase a Ruger MKII and need to find someone to thread the barrel for a supressor.  Does anyone know who can do this work and how much it costs?

Lots of times the suppressor manufacturer will do the barrel threading, and who would be better qualified than them?

Other than that, any gunsmith worth his salt should be able to do the threading for you. Just make sure that they are aware that this is going to be used for a suppressor and it will need to be precise as to prevent baffle strikes.

Search around and try to find the best gunsmith in your area.

Also, take into consideration that the theads may need to be a certain size (?) and right handed or left handed.  I think different suppressor companies make some that screw on/off in different directions.  (don't quote me on this)

I wrote Gem-Tech for their opinion.  I'll let you know what I find.