YepIs a brass from a fn five seven pistol, or military equivalent(think they made some rifles for military in same caliber). Fairly new, less than 30 yrs old. If fn uses the same nomenclature as others on their brass 07 could be the year.
Especially when using the fire rate of something like the fn p90. Made to punch holes in stuff with low recoil and high velocity. Also for OP it was introduced in 1990 so not terribly old.Yep
The 5.7 X 28 can be a MEAN ! little Round.