Did the Finns blue the Mosin Nagant bolts?
Yes it does seem this happened but only rarely. It is not known just when this was done (or why) but it is clear that at some point it did. Still this is a rare item to encounter. The rifles can be Finnish or Russian in origin. At times one will see a new serial number on the rifles with blued bolts that start in 00-0 and it is thought this might be an armor’s gun. This is a guess at this point and can not be backed up.