Occasionally I see something on these boards which makes it extremely difficult for me to keep from simply posting "what a load of crap". Marksmen's posts are a classic example.
Made of better materials? Give your head a shake. Virtually all, production or custom, use similar materials. Custom actions are "heat treated and hardened". Do you think production actions are not? Most custom BR actions are quite soft since it is accepted procedure to heat treat prior to final machining. Hence the problems with galling of the locking lugs (stainless has always been problematic in this regard). Barnards and RPAs (neither of which is recognized as a popular BR action in North America) are exceptions and are hard. These actions must be ground to final dimensions. All that I have checked were perfectly straight and concentric and yes, guys, I am capable of accurately checking and, if need be, correcting, an action.
My understanding is that Greg Tannel does good work. He uses common machine shop fixturing methods and his methods are sound. They are much the same as many people had been using prior to Tannel's adoption of them. Such fixtures and set up techniques have been in use in industry since before any of us were born.
Now, as to whether there is a demonstrable improvement subsequent to the truing of a Remington or any other action is hard to say. It's hard to say simply because nobody I'm aware of has done any scientific testing to demonstrate such improvement (or not). I would not be surprised to learn that such testing had been done by some one like Sam Wilson back in the 1950's but I've not heard of it.
The use of Remingtons or any other factory actions has largely fallen by the wayside but this is related as much to the different face of BR today as anything else. There are fewer experimenters shooting short range BR than in the past. In addition most prefer to own custom actions. There is nothing wrong with pride of ownership but there is also nothing wrong with experimentation.
I'm pretty sure Dennis built his first BR rifles back in the early seventies (he's much older than I!). Like everyone who posesses an open mind, his methods and results have changed and improved over the years. I do things differently now than I did 30 years ago. So does any other gunsmith who seeks to improve his product and his knowledge. Nonetheless, neither Dennis nor I will try to tell you that you are as well off with a trued Remington as with a Bat or Nesika Bay. We will tell you that it is a viable alternative which can work out just fine.
In the final analysis, todays custom actions are better than have ever been available before but at the cost of them, they should be. The Remington action is still a viable choice for the man who wants to do his own accurizing or who has the action on hand and doesn't want or can't afford to cough up the 1500.00+ for admission into the elite custom action club. Will the rifle be worth as much? Probably not but it might shoot as well as most. Maybe even better than most. It will at least give the shooter a place to start and not a bad place either. Regards, Bill.