My M&P40c has developed a couple small spots of rust on the slide several times, and it isn't due to lack of care. It's been because I carry IWB day in and day out, rain, snow, or shine, and the gun is exposed to sweat and the elements on a regular basis. A quick wipe down with an oil-impregnated cloth as soon as it's noticed, removes the rust easy enough. It's a gun. I don't baby it. The thought to send it back or to complain about it never really crossed my mind.

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NRA Pistol,PPITH,PPOTH&TASER