What would be your guess with a new custom gun? I have taken it out of the stock & everything works good but I have not found where release is binding against the stock. 2nd question, If you had never seen a McMillin stock how would you know if it was or not? BTW I don't use WD-40 on anything other than bolts & nuts.
Put a thin coat of inletting black or Prussian blue on the bolt stop. Put the barreled action back in the stock and look for signs of the inletting black or Prussian blue on the internal surfaces of the stock.
FWIW, I have several McM stocks and have yet to have an issue with the bolt stop not working. My next build(d) will see there way to having side bolt releases installed, though.
