I always disassemble and clean new magazines.
Some, like the M&P .22, had grease in them.
I have found some springs upside down.
I spray with CRC silicone, wipe dry, and reassemble.

By the way, with semi-autos, letting your fingers touch the slide when firing can cause malfunctions, also. When you load the first cartridge, let the slide slam shut; don't ride it down.

__________________
Science plus Art