I have actually had a few examples of this coin, so it is not as rare as its not being in RIC would indicate, plus there were four examples of this type in the Bikic-Do hoard, # 198- 201. One from officina A, one from B, and two from epsilon.
Constantine I
A.D. 319
18x19mm 3.7gm
IMP CONSTANTINVS AVG high crested helmet, cuir., spear across right
VICTORIAE LAETAE PRINC PERP [ Joyous (well-earned) victory to the eternal Prince] two Victories stg., facing one another, together holding shield inscribed VOT PR [VOTA POPULI ROMANI (vows of the Roman people)] on altar.
ESIS dot
should be before RIC 61
unlisted for bust type H11