Help - ID this mag base part

[Battering ram NIB]

Found this ontop of one of my shelves. it most likely flew off years ago. I cant figure out which magazine it goes with...someone impress me with your knowledge?

 

[Loco]

I assume that's a 9mm Luger round?
Have you ever owned a Beretta-style .25 or .32 pocket pistol?

 

[pjm204]

Looks like sten mag to me.

 

[Battering ram NIB]

Winner...yes its a sten.....I knew it was a subgun mag and had taken a few apart to check, but didn't check the sten yet....thanks!!

 

[pjm204]

No problemo. I was pretty sure I knew what it was and then I confirmed. Glad I was right. Hopefully you can figure out which mag it goes to! I know I have a whole bunch of Sten mags.