The only frame I have seen like that is the STI 2011 , so my guess would be that its a custom using an STI frame and custom slide. I closer or bigger pic would help to.
I've seen some guys machine some funky stuff into slides to drop weight and increase the coolness factor
Maybe E-mail Shawn Carlock he does some pictol work ,he may have seen that gun or have a better idea on what it it.
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