Caligula bronze? Odd portrait

About the only letters of the obv inscription are a pretty clear "GER" (GERMANICUS?). But the portrait appears to be a radiate bust. I flipped through Wildwinds and couldn't find hardly any Caligula that were similar.
Edit: 27mm and 10.6 grams. Appears to be brass.
Thoughts?
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My guess would be Domitian. The radiate portrait on dupondii was well established by his reign, many of his obverse inscriptions include GERM for the title Germanicus, and the reverse could be a Virtus standing right type, which is known for Domitian.
Thank you, I will keep searching for a match.