My most recent XD purchase, a like new 4" Service, .40 S&W, (I don't think it had more than 100 rnds throught it) has experienced an occasional failure to feed, both with it's original guide rod and the replacement Don's rod and 22# spring ordered from Pistol Gear. I'm using the same ammo and magazines that my other 3 .40 XD's perform flawlessly with. I have polished the feed ramp. When the FTF occurs, the round is sitting in the lips of the magazine, nose against the feed ramp and slide against the rear of the cartridge. A very slight rearward motion of the slide will allow the round to tip nose up and then chamber. The incidence of this occuring seems to be diminishing as I have run several hundred rounds through the pistol. I'm convinced this is the break-in period some XD's seem to require, however, was wondering if a lighter guide rod spring may allow the action to operate faster and overcome this breakin period quicker. None of my other XD's experienced this problem--2 new out of the box and one slightly used when purchased. Any thoughts would be appreciated.