Just bought my M&P 45 a few weeks ago. Love the weapon, but I have a problem with it that I can not understand. First of all the trigger feels "gritty" like it has sand in it. Are all the M&P 4 triggers this way? But my biggest problem is I have failure to feed on the last round. It's fine 1-9 but on that last round it won't feed. I thought it was maybe a bad mag. so I switched to the other one , and same problem. Any ideas before I send it back to smith? Anyone else have a problem like this? I can't even get through a box of 50 without this happening at least 3 or 4 times.