This is a discussion on USGI M14 barrel data base - 7791362 within the Reference forums, part of the M14 M1A Forum category; Updated
Springfield Armory (S A)
Canadian Arsenals, Ltd. (C A)
Take a look at this barrel SAK NM part number and its chrome lined ,even has the start of flake on one land . NM has been x'd out
I just cross referenced Different's thread on 7790190 barrels, SAK was making 7791362 NM barrels and 7790190 chrome standard barrels at the same in 6-85. Must be a factory mixup, either they accidentally put an NM barrel in the chrome tank, or a 7790190 chrome barrel was just mismarked as a 7791362.
I would think it would be the latter, since chrome lined barrels start with a slightly oversized bore to allow for the thickness of the chrome plating, where NM barrels are cut exactly to spec. I would think if you put an NM barrel in the chrome tank, the bore would come out undersized and it would be scrapped.
Very interesting, as I always say on the job: "When it comes to ordnance, never say never."