Re: brand new sendero acting up
People have reported various and similar problems with all makes/models of new firearms including the Sendero.
The common theme is that any modifications you make will likely void your warranty.
Hopefully, it will be something simple that your smith can rectify swiftly and inexpensively.
Once he has a diagnoses, it might be worth a call to Remington before he starts machining anything.
For example, ...supposing the chamber is cut poorly, maybe they'll let you send in the barrel for an exchange and in the meantime you could get a $60 takeoff from the classifieds in these forums. Otherwise, it may be time for a Kreiger, Bartlein, or Shilen barrel thus making the most of a bad situation.
The sling swivel stud on my Sendero originally protruded enough to rub the underside of the barrel. I discovered it before firing and got after it with a Dremel. I don't imagine it would've done any good for accuracy had it gone unnoticed.