This coin is not listed in RIC for the obverse legend (1b) or the bust type (G12). It should follow RIC VII Arles 58. It is listed in Ferrando as #323, illustrated by the same example below, which is a die match with this coin. No measurements were given for the coin.
Not in RIC exampleMaybe a little pricey at $1,048
Constantine I
A.D. 315- 316
IMP CONSTANTINVS AVG; laureate and cuirassed bust left with shield on l. arm, holding horse by bridle with r. hand.
SOLI INV-I-CTO COMITI; Sol stg. l., chlamys across l. shoulder, globe in l. hand, raising right; S/F across fields.
In ex. QARL
RIC VII Arles – , Ferrando 323