You said this was a new gun, right? The common causes of FTF malfunctions, other than limp wristing, are: magazines, needs to be cleaned, or ammo related. It could also be due to some rough spots on the feed ramp, breech face, or a burr on the extractor.
I'd start by cleaning and lubing the gun. While doing that, inspect the feed ramp, extractor, and breech face. Check your magazines and make sure they are in clean and dry. Make sure the followers and springs move up and down without kinking or binding. Make sure your recoil spring assembly is working correctly, and not binding or kinking. Assemble the pistol, and see if the grittiness or roughness when racking the slide is gone.
If the pistol seems to be in working order, use some good quality FMJ ammo for test firing. (I also like to load new magazines to capacity and let them sit loaded for about a week before the initial firing.) If you still are having FTF malfunctions, ask someone else to try shooting the gun...these guns have a heavier trigger than other pistols, and it could be affecting your grip. When you are shooting the gun, make sure your thumb isn't hitting the slide release.
If none of this helps, I'd call S&W. There may be other suggestions that others here can give you to try...before you call S&W.
Good luck!