Yes, there is a turned metal barrel for BT-42. The Kuivalainen shop offers a very nice product that has a beautiful muzzle brake with all the holes drilled out. This is his addresshttp://www.kuivalainen.biz/
It was under a update as I visited minutes ago but should be online shortly.
Here is my build. It still is missing the etched part that comes in front of the muzzle brake.