Sounds, as they say, too smart by half.
Slip a small pocket knife in your pocket, or add one to the butt-stock or hand grip storage. Even the smallest, cheapest and simplest pocket knife is going to be better than a sharpened magazine spring.
Also, at some time in the future your going to want to disassemble those magazines for cleaning and inspection and odds are that if one of the springs is sharpened your going to forget about it and fillet a finger.
I heard about a guy hiding a razor blade in his shoe. He forgot about it until one day he slipped on his shoe and the blade laid open the sole of his foot. Evidently it had slipped out of position and turned edge-up when he slid his foot out the last time.
Beware of potentially dangerous stuff hidden and forgotten. You will forget it when you need it and it can come back and bite you.