Roman Empire, Gallienus Antoninian - unpublished

Gallienus AR-Antoninianus, struck at Milan mint.
Obv: GALLIENVS AVG, radiate bust with bare back and large aegis on strap left.
Rev: VIRTVS AVGG, Hercules standing right, holding club and lion skin.
Ø 20-24 mm 3.12 g.
Not in RIC and Göbl, apparently unpublished.

Curtis Clay and his friend Markus Weder kindly provided me with some additional information:
"Other examples of this rare bust type on Milan coins of the same issue: Göbl pl. 82, 1034u (rev. MARTI PACIFE, P in l. field); pl. 84, 1044u (rev. VIRTVS AVGG, Hercules stg. l. holding branch, club, and lionskin). Neither ill. spec. is from the same obv. die as your coin.
Other AVGG coins of the same issue at Milan: pl. 84, 1044u, just cited; 1045o (apparently from the same VIRTVS AVGG rev. die, different sort of armored obv. die). Pl. 72, 937z (ADVENTVS AVGG Emp. on horseback, obv. of Saloninus as Caesar). Pl. 71, 929r (bronze medallion, ADLOCVTIO AVGG Emp. and two attendants on platform addressing troops)." Markus Weder knows of just one other specimen of my coin, ex Gibraltar hoard, it is in his own collection.