I have recently purchased a Savage 330, 12 gauge O/U, made in 1970 by Valmet of Finland. This gun has a 28" F/M barrel set. They also offered a 26" M/I set and I understand that the barrel sets were interchangeable. One contemporary ad left me with the impression that you could even swap the 12 with a 20 guage set. Does anyone have experience with this gun? Have any idea where barrels can be obtained? Would other Valmet offerings such as the Model 412 have used the same barrels? Thanks for now.