This coin is a bit rough, but is a fairly rare type and has a bit of a story as it was issued for Constantius II and Constantius Gallus before the campaign against Magnentius, but the reverse was premature as Constantius II suffered setbacks and even lost Siscia for about a month before his actual victory over Magnentius.
Constantius II
A.D. 350- 351
16x18mm 2.4gm
DN CONSTAN-TIVS PF AVG; pearl-diademed, draped and cuirassed.
VICTORIA CAESARIS; Victory walking left holding wreath and palm branch.
In ex. (?)SIS
RIC VIII Siscia 315