nwgunman, I just swapped a .38 super to a 9mm drop in bbl. No name bbl, don't even know who made it. Check out my post in Range Reports, "9mm conversion". End result I like them. With the quality of machining today I don't see any problem with them.
It's possible ,but not likely. Someone with the specs & tooling to measure can confirm that. Some play is not unusual. JP Interprises sells an "elevated" mag catch that raises the mag .045" in the mag well. More likely, it's due to extractor, mag, feed ramp ,spring rate issues, but it's not the "junk pile" for your gun yet. If there is a problem with the frame, Springfield will gladly make it right. They have outstanding customer service....Maybe the mag catch hole was machined too low in the frame? I checked the catch itself (looks ok), and even swapped it out with a nearly new McCormick and there's the same amount of "play".