RE: Custom vs stock guns
In my experience Remington' s custom shop will furnish you a fine gun. Winchester' s will too.
A typical custom gun from a smith that is good will run $2,500 and up. A lot hinges on your needs for fancy wood and engraving and special checkering.
There' s a lot more to a custom gun than accuracy....If I agreed to take posession of a .300 Weatherby custom, accuracy would be acceptable to me at 1.25MOA however if it was a .22-250, accuracy would have to be well under 1.0 MOA.
I' d be far more critical of finish, checkering, feeding and extraction, trigger pull and other functional things.