Just an update. I got the pistol back from Springfield-- so far, so good (200 rnds). According to the paperwork they reamed the chamber, polished the feed ramp (it looks the same to me), replaced the recoil spring (standard weight, but it feels slightly stiffer now), and replaced the extractor.
I removed the barrel and dropped a round in. It moves ever so slightly in the chamber. If accuracy is reduced, I haven't noticed as it's still more accurate than me.
They also must have tightened the slide to frame fit, because there's no longer a bit of play in it. That wasn't noted on the paperwork.
A+ for their customer service. It was back to me in a week and a half.