Roman coin identification 050425 [solved]

Can anyone help me identify this coin?. 

I believe it is a bronze nummus from around the Constantinian era. 

The diameter is 15.8mm. 

On the back it features a figure that I believe is winged victory. 

I can't find an exact photo match.

Thank you all

It's Gratianus. The obverse text is DN GRATIAN…
The reverse is this design: https://en.numista.com/catalogue/index.php?r=securitas&st=1-2-79-80&cat=y&im1=&im2=&ru=129&ie=&ca=3&no=&v=&a=&dg=&i=&b=&m=&f=&t=&t2=&w=&mt=&u=&g=&c=&wi=&sw=

https://numismatics.org/ocre/results?q=authority_facet%3A%22Gratian%22+AND+fulltext%3Asecvritas

A thousand thanks. I'm new to the site and I'm really excited because it's helping me identify a handful of Roman monets that I had never managed to catalogue. thanks for the help 

Manlius