My M&P 40 has hundreds of rounds through it, never had an issue. Tried Fiocchi 170gr today and had almost a dozen feed jams. I think the Fiocchi bullet has a slightly smaller flat nose than normal. Some quick Googling shows others have experienced similar issues with that ammo with M&Ps and I also saw a Walther P99 mentioned. I won't be using that ammo again. If the jams stop I will chaulk it up to definitely being the ammo. PS. It's loaded pretty hot. Much muzzle flash as well.