Tim...I only have 4 barrels "in hand"; 30-30, 223 ultra, 44 mag and 357 mag. They all say SB2 on them. I do not think H&R would put a barrel marked SB2 on a SB1 frame; would they? Do you know if the "new" 44 and 357 barrels will be marked SB1 or will they have no markings as to frame? I know this is a stretch, but how is a fellow to keep all of the frames straight if they are not marked and have to rely on serial numbers.