Depending on the date of manufacture, it could possibly be the result of the conversion that the factory was pushing to allow the bolt to open while safety is still "on". Opening the bolt with the safety "on" was not possible in the older model 700's. A gunsmith recommended to me not to have it done as he had several complaints similar to that described in the first post. Other than the problem with the conversion, I have never seen or heard of the bolts coming open when the bolt was closed.