Constantine helmet designs

[livingwater]

I just won this on ebay Savoca for $47, Constantine I, Siscia RIC VII 54 with horseman on shield.  Victor, I looked at the ones you have for sale on Vcoins.  Yours with horseman left is cool.  This one is rather worn and rough.  It has a helmet design I don't recall seeing before.  There are numerous designs on the helmets, stars, dots, crescents, chi-rho, etc.  This one appears to have a rosette or wreath in the middle, inside may be a star or X?  At first glance I wondered if it was a chi-rho with retrograde P, just wishful thinking.  Below this are two dots with vertical line between.  I zoomed in on the helmet but it goes out of focus.  When it arrives I'll take a closer look.  20mm 3.14g     

The chi-rho has a circle around it on the unique AR medallion of Constantine I.  Do you know which museum has this coin?

[Victor]

Hello Mark. I was the underbidder on this coin. The design is unusual but I have had a similar example which I have posted below. They are not exactly the same, but close.

I have a couple of pages on Siscian VLPP's --

http://www.constantinethegreatcoins.com/sis/

[livingwater]

Sorry I didn't know I was bidding against you.  I mostly collect Roman Provincials, so we likely haven't been bidding on the same coins very often.

[Victor]

It's not a problem at all...it goes with the territory. I only mentioned it because I thought it interesting that at least two people noticed the unusual helmet. I am glad that you got it though, as I would have eventually put it up for sale.