I went with frog lube on my new M&P40c after watching several "youtube" reviews. Among the best for rust prevention. My wife loves the fact that it is non-toxic and smells good. My results are superb.

Treated my new pistol twice (including the firing pin). Luckily we had a spare hair dryer to dedicate to the task. Went to the range today and fired 200 rounds. No problems at all.

Marcus