What Ninja and Rick said!
As soon as @bad ninja posted that, I felt foolish for even considering an alternative. I will get the other spring @Thawarlock suggested for the future, but 1 FTF in 40 rounds is unacceptable. It should work flawlessly as shipped from the factory - it's not a Bryco or Jennings.What Ninja and Rick said!
This is very often associated with a poorly fit extractor - excessive deflection and/or too much tension. This is not unusual for production line 1911s. By all means send it back to get it squared away.Many remedied by a bump on the rear of the slide with left palm.
Send it back & tell em you have 550 miserable rounds thru it.I just bought a new camp guard last week, I took it apart, lubed with cp-10 and proceeded to shoot and clean every 50. Constant FTF and occasional early slide lock. I just passed 250 rounds and I have noticed no changes. At 501 rounds or the very first malfunction after 500 it's going back, let them break it in with their ammo!