Constantine I MARTI CONSERVATORI from Rome

[Victor]

This coin is not in RIC for the bust type and Mars standing left versus RIC with Mars standing right.

Another example http://www.notinric.lechstepniewski.info/6rom-364.html

Constantine
A.D. 313
22x24mm    4.0g
IMP C CONSTANTINVS P F AVG, laureate and draped bust right, seen from rear.
MARTI CONSERVATORI, Mars standing left, head right; right leaning on reversed spear, left on shield; ✶in left.
In ex. R S
RIC VI Rome –