Oooohhhhhhh, now I see what you want to do....
I don't know of a part off the top of my head that will do that.
And you should probably stop there, while you are ahead.
In order to use the pistol, if it's the one I am thinking of, doesn't the rail on the pistol move with the slide? Or is it separate? Because if the rail moves with the slide, there is no way the weapon would cycle...
JD