Perhaps the 1/4 inch is referring to the bolt carrier closing since it is a camming mechanism that magnifies a failure of the bolt to rotated to the fully closed position. Also if the the gauge is out of spec the + error is likely greater than 0.00015. Maybe it is really a field or no go gauge and was mislabeled.Forester says gauges are precision ground to + -.00015. If the gauge was long by +.00015, thats 1/26 of an average human hair (.004). Can't see that turning into a .25 (1/4) headspace error. Wrong marking/bin: okay. Let Forester sort that out, get a refund.