this coin is not in RIC with this bust type. Also not in Bastien or the supplements.
another example-
http://www.notinric.lechstepniewski.info/7lyo-92_h2l.htmlConstantine I
A.D. 320
18mm 2.3gm
CONSTANTINVS AVG; helmeted and cuirassed bust left, spear across r. shoulder and shield on l. arm.
CONSTANTINI AVG in three lines around VO/TIS/XX
In ex. •P•L•
RIC VII Lyons --