I had feeding problems with my M&P 40 right from the get go. I bought it new from FS, cleaned it, and heat treated it with FrogLube. Later that week when I shot it for the first time (shooting 165gr PMC and 180gr Fiocchi) I had at least 5 failure to feed with both brands of ammo. I shot 100 rounds of each and the FTFs each time was the round not fully chambering or jam somehow on the feed ramp. I plan to polish the feed ramp this week, hoping this will fix the problem but if not then I'll be calling S&W. Also the jams occurred in both magazines that came with the firearm so its probably a firearm issue and not the mag or ammo. It sucks even more because this is my first handgun and I chose it over the P226 and Glock 22.
Update: I also shot 200 rounds of Winchester white box and American Eagle yesterday with the M&P40 and still had 1-2 jams with each ammo.
One or two jams per how many rounds? Some of these pistols need a break in, like it or not, they are mass produced machines with parts that don't always work together right out of the box. I would lose the Frog Lube and lubricate the pistol heavily with 20w synthetic motor oil and blast away. 500 to a thousand rounds is not an uncommonly long break in.