I had Montana Rifleman build me a barreled action about two years ago. They had a sale on WSM barreled actions, and I got a blued version for about $800. I got it in 270wsm. The gun will consistantly shoot .5-.75" groups. Which is pretty accurate, but out of a custom setup, I might want a little better. This is the first "custom" barrel I had ever had, so I really don't have much experiance. However, I find the barrel very difficult to clean. It collects a lot of copper, almost as much as my other factory rifles. It is my impression that a custom barrel should be easier to clean than this. I think the action is great and super strong. I put the rifle in a Accurate Innovations laminated wood stock for about $400. If I had it to do again, I don't think I would go with them. At least I would not use there barrels. Maybe their action.
I am now building a custom 7mm STW off of a used remington donor action with a Broughton 5C barrel. I expect to get .25 to .5" accuracy and a lot better cleaning. I have $300 in the donor gun, $350 in the barrel, and about $500 in gunsmith fees for blue-printing, and installing a SAKO extractor. It is a little more than the barreled action from MT Rifleman, but I am sure I will get better results. The other thing to keep in mind is you can get a new custom action like a Stiller Predator that might not even need blue-printing for about the same cost that I have in my donor action and gunsmihing......
Just my $.02
Joel