Hi all. I just went out and bought a 4" XD service model. I shot my friends XD and loved it so I bought it!! Anyways, I chose the XD40 for the stopping power over the 9mm. I just ordered a barrel conversion kit to 9mm on pistol-gear.com(Cheaper ammo to go range shooting!). I was wondering if I needed a 9mm clip along with the barrel. I heard that the .40S&W works with 9mm..although I don't know how reliably..THank you.