I have been doing some more reading and have been trying to find more information about micro groove barrels. How long they were used? if they may be Bofors barrels if they do jot carry " bofors steel" above the stock? If not, who made them? Also, on the note of heavy barrel microgroove barrels, were there a standard diameter or, like I have been discovering about sakoism's are there some variations that don't fully make sense when compared to when the rifle was built? If someone could shed some information it would be very much appreciated thank you.