Armor scale vs. mm

Not even....

"120mm-ish" figures/accessories are close to 1/16th scale.

"75mm-ish" figures/accessories (not very common these days) are close to 1/24th-1/25th scale.

But...keep in mind that the "mm" scale is really just an approximation....historically based on display size needs; as opposed to an actual "scale". Remember the classic Series77 "The Americans" figures in an advertised 90mm scale? The Verlinden 120mm heads...were more often than not, too *small* to use as replacement heads on these 90mm figures!