Just curious, if you own a M&P Pro, how is the rifling condition of your barrel.
I am sending mine back due to poor machining at the muzzle end, especially.
At first I thought it was some sort of build up due to the discoloring I detected,
but after cleaning failed to remove it, I looked more intensely. There must
have been a broaching tool defective while machining. I have to send it back to
S&W after 2 days from purchase.
Here is what I found: