I just now swapped the flat base plate from my Kel Tec PF9 onto my wife's BT380 mag. As I expected it was a good fit, you would need to open up the round hole so the pin on the BT380 mag plunger goes in, however. I don't like the flat plates, my hands are just a bit too big.
I tried the modified mag in the BT380, too. It fits fine...
If you can't find any where you are, PM me and I'll mail a flat PF9 plate (I have 2) to you.
Last edited by RobO9mm; 10-27-2012 at 10:48 PM.