Constantius II, FH3 Siscia mint, probably late 355 to the end of that decade - mintmark ASIS with Siscian letter following that looks like a backwards Z. Judging from the size of the fingers, I suspect this is a small AE3 from the issues that makes separating RIC 352 from RIC 361 impossible. It also is from the period where new finds relating to the headgear on the horseman make assigning numbers uncertain. I would prefer not to hang a number on this one.
I found this coin in a roll of pennies a few years ago and i am trying to identify the coin i have no clue but looks very familiar to the coin posted in this thread to me .
It's one of the later Fallen Horseman types. I'm guessing Julian II based on the obverse portrait, but without an obverse inscription it's probably not possible to be 100% certain of the emperor. Constantius II and Constantius Gallus are also possibilities. Can you tell if the last few letters of the inscription are AVG or NOBC? How big is the coin? Pretty amazing to find one of these in a roll of pennies.
You need no legend to tell AVGustus from NOBleCaesar since the portrait of the last will have no diadem or other headgear which AVG would. Legend would be nice to tell Julian from Constantius Gallus. The S in the reverse field suggests the coin is earlier than Julian. The image below shows a Constantius II Augustus with obvious ties to the head decor behind the head. My guess is Constantius Gallus. Mine is Thessalonika but your mintmark is off flan so only style will allow a guess and that requires someone more expert than I am.