I recently got a preowned GI lightweight 4" champion from gunbroker. Very durable but had two issues:
a) would not feed HP ammunition of any kind
b) exjector flung brass straight back smaking me in the forhead unless I shot "half-homie" style
The good news is that Springfield's customer service is among the best on the planet. I called and explained my problem. They emailed me a shipping label and a week later I had my gun back. The first problem was solved by polishing the barrel and frame ramps. The second was solved by installing a 9mm extended extractor.
So far everything works great and I plan to start working it into the daily carry rotation.