First, I have to agree with Mr. Richard that internet
nail-biting can certainly "snowball." On the other hand, when you have shooters with a lifetime of experience telling you that there is a decided accuracy problem with their randomly purchased M&P9, their stories at least deserve to be considered with respect to their considerable experience.
I did not get to re-crown the barrel of my 9L before I tested it again last evening, but I have done so now and will know more the next time I shoot it. I doubt that there was anything wrong with the barrel crown as it came from S&W. It was a tad rough, but the crown was well centered, probably cut before the barrel was rifled, and it lapped in to a smooth finish very quickly.
Last evening I had limited time and did not get to shoot much, but here are some additional shooting results from my 9L (serial number (MRJ0xxx). Barrel was clean when I started. 5 shots were fired to condition the bore. All measurements are for 5 rounds at 25 yards, from a benchrest:
Federal 9BP / 3.38"
Magtech 124gr FMJ / 4.81"
Rem 124gr JHP handload / 3.44"
Montana Gold 121gr IFP handload / 6"
Both of the handloads are exceptionally accurate in other guns I own. I do not have any concerns about the quality of those cartridges and consider them at least the equal of similar U.S. commercial ammunition I have used. Unfortunately, I did not have time to fire three 5-round groups with each load.
Thinking that the Rem 124gr JHP handload might do better if tested again (that loads has always been exceptionally accurate in many of my guns), I decided to take my time and shoot one 10-round group before the range closed - 7.38"!
This "group" contained four flyers, possibly three and one might have been a slight shooter error. In any case, if those four were subtracted from the results, the resulting 6-round group would have measured 1.81".
Every group mentioned above had what appeared to be 1 or more flyer(s). For instance, the initial group fired with the Remington-bullet handload would have measured 1" were it not for the single flyer that took that group to 3.44". The flyers are not a matter of first- or last-shots.
With due respect to Mr. Richard's legitimate concerns, after over 40-years now of shooting more centerfire handguns than I can recall, I have confidence in my ability to know when I have fired a good target and when I haven't. For some reason, this gun shows signs of potentially being a good shooter, but is erratic and consistently produces flyers. I do not claim to know whether the problem is systemic across a wide number of production guns. I do claim that I expect a gun of this quality and price-level, and certainly one made by a highly respected and long established company like S&W, to shoot with a certain level of precision. Based on my experience with other, similar, production guns from several manufacturers, this gun should
average 3-inches or less at 25-yards, 2-1/2" better. This particular gun will not do that with any ammunition I have tried so far.
In looking at the various dimensions of the barrel and slide, there is nothing obvious that indicates one part or the other is substandard. The interior of my barrel does appear to be slightly larger at the chamber end than at the muzzle, somewhere in the area of 0.0005", which I would think would work in favor of accurate shooting as opposed to against it. I do not have gauges to check the length (headspace) and diameter of the chamber itself. All ammunition used would easily drop into my Wilson maximum ammunition gauge.
I did have the chance to speak to the folks at Bar-sto today and while no specific information was forthcoming, they are working on a barrel for the M&P. I have confidence that their product will likely cure the worst of my gun's problems. It will be probably April, 2013, or later, before I will know more about that.
