Originally Posted By Walkure:
Yes, it will fit the frame.
No, you cannot generally load 9mm into .40 mags. The feedlips are too wide; even if the rounds were retained at all, they would tend to unload themselves out of the mag without much provocation.
Correct, unless they are the new Mecgar AFC magazines with the blue follower. They feed both .40 and 9mm just fine. The last USPSA match I shot, my buddy and I shared magazines in Limited, he was shooting 9mm minor and I was shooting .40 major.
You could not do this with the black follower magazines, just the new ones with the blue follower.