I just bought a Finnish M-39 (300,000 sn range)and wanted to know the proper ammo to use. I know its caliber 7.62x54R however, in the book "Mosin-Nagant rifle" by Lapin he states (on pg 117) "Finnish rifle bores were tighter at 0.3082 to 0.3095 inches than Russian bores at 0.310 to 0.311 inches and there was a possibility of dangerously high pressures if the larger diameter round was used in the tighter Finnish bores." He talks about the new "D" round was the proper ammo. Does anyone know anything about this? Is all 7.62x54R surplus ammo found these days the "D" round? What are people shooting in there M-39s. I did check out 7.62x54r.net ammo page. Thanks