The bust on this coin is raising its hand, “showing Imperatorial gestusâ€. RIC 46 has this “gestus†with laureate and cuirassed bust. It is not very clear on this example, but it looks like Constantine might be holding a globe in his left hand and he also appears to be draped and cuirassed, if so this is an L3 bust, which is unlisted and should come after RIC 46.
I hope it will be clearer when I get the coin.
Constantine I
A.D. 315- 316
20mm 2.9gm
CONSTANTINVS AVG; laureate, cuirassed and raising right hand.
SOLI INVIC-TO COMITI; Sol rad., raising r. hand, globe in l.; stg. l., chlamys across l. shoulder. TF in left field, star in right.
in exergue PLG
cf. RIC VII Lyons 46