To be honest, I don’t really know, but SIGSauer has a very complex German/Swiss/American genealogy. Has an American offshoot in NH, but I don’t know if it has a manufacturing facility there, or just imports.
Good, well respected products. My major concern is the high chamber pressure, and consequent barrel wear. I was quite partial to the M-14, especially w/shortened barrel @ +/- 60k psi pressure as opposed to the 6.8x51 Sig @ 80k psi...but I don’t know about the ballistics downrange. If they’re similar, I’d opt for the M-14...but then again, it ain’t my decision.
Chamber pressure has little to do with barrel wear. Barrels wear mostly in the throat area which is the first couple inches forward of the chamber. It's primarily caused by heat and shoulder angle/throat length which controls the angle at which the gasses impinge the throat area during firing. Powder amount and type also have an effect. M16/M4 barrels have been chrome lined forever and I assume the new rifles will be the same. This greatly reduces barrel wear, almost eliminating it. It's almost impossible to wear out a chrome lined barrel. Even in wartime the average infantry rifle isn't shot nearly enough to worry about barrel wear, far more wear is caused by excessive cleaning than shooting. Even if you could manage to wear out the barrel of the new round, which isn't likely, barrels are cheap and easily replaced.
Of all the things to worry about with the new rifle, barrel wear is far, far down the list.