Anybody find the "NSN" weapon yet?

[=яενєηąŋŧ=]

Working through unlocking all the gun parts, and this set has been bothering me. Available to install on a lot of the Europan weapons, but none of them seem to unlock the parts.

Thought it might have been the R11 RSASS because it *only* takes NSN parts, but got it to level 12 and nothing. (Also, don't use the R11 RSASS, it's awful)

[Jinx]

Same here

[Chotato]

Same issue. Never seen anything called an NSN but have plenty of parts for one.

[Aren]

could it be something not sold but only from quests or dropped?