OG107 Utility Field Cap (1977)

Shown one size 7, 1977 dated. Seem very common and popular among Army Rangers in the 1980s, but really hard to find in nowadays. Another weird thing, the NSN of the this cap referring nothing or “NO ITEM NAME AVAILABL” in all databases. The only thing I can figure out is the NSN is not completely nothing, I found the NSN of this cap (size 7) is in a continuous sequence of five similar “not much valid” NSNs in some databases. So I made the NSN-size chart based on other headwear which has five sizes (like ERDL Hat).   Stock Number Reference:

Cap, Utility, Field, Cotton And Polyester, Poplin, OG-107

Assign Date: (Acquired)
NSN-Size Sheet (Speculated)
Size NSN
6¾ 8405-01-011-9318
7 8405-01-011-9319
7¼ 8405-01-011-9320
7½ 8405-01-011-9321
7¾ 8405-01-011-9322