Are there any? The only aftermarket premium barrels I can find are threaded. I'd even settle for a 2.0 OEM barrel, but I can't find them either.
I read this so I've been looking.
">What's wrong with the barrels? M&Ps aren't very accurate. The Gen1s were inaccurate, and S&W tried to remedy it by changing the twist rate from 1/16 to 1/10 which didn't fix it. When they were going for the MHS contract and developing the Gen2 they realized that they could in no way make the accuracy requirements so they improved the issue with the Gen2s. Some say that the issue still persists somewhat with the Gen2s. APEX started their fitted barrels to address the Gen1 problem, and they also offer Gen2 barrels. My pet theory is that the M&P design unlocks the barrel early, and unless the barrel is tightly fit to the slide it causes inaccuracy."