Are you saying the barrel needs a light film of oil on it to operate?

Love my M&P's, but I'd expect better reliability. This is really going to excite the wolves looking for a weakness in the Shield.

If the tolerances are so tight between the barrel and the slide that it will hang up unless a film of oil is there, what happens when a speck of sand or dirt gets in that gap?

My M&P's don't hang, but I haven't tried wiping them down with denatured alcohol or anything and trying them completely dry.