Hello. Yes, the frames are the same. I THINK you might have to use the 9mm ejector rather than the one that comes with the forty version as the latter is wider and won't work with the 9mm slide as it has a notch that is more narrow for the 9mm ejector. This may have changed as I've not compared the two in several years.
hello i have a browning hi power that has a 40cal slide on a 9mm frame,that was converted too 9mm.it shoots great i love it !!cylinder and slide did the work! sadly its at another custom shop getting repaired from the custom work that cylinder and slide screwed up,i do not know what they did too make the conversion work? all i know you can convert a .40 slide too a 9mm !!hope this helps !!
I just acquired a 40 top end for the purpose of assembling a 40 HP on a frame I bought last year. I've not been a 40 fan, but decided to give it another try on an HP. Previously had a Glock 23 that I converted to a 19. I didn't like 40 in that platform.