smith and wesson sigma accuracy

N

nathanl

Inactive
My brother recently bought a used s&w sigma in s&w.40 and it has a factory ported barrel. It is fairly accurate at about 10 yards but back up to 25 and it is just incredibly inaccurate as in not even hitting paper probably 5 out of 10 shots. I wouldn't say either of us are the best shot in the world but I can shoot about a 4 inch group at 25 with my 1911 and he can do about the same with his fnh 9mm but we both have the same result with this .40, sub 2 inch groups at 10yds and barley hitting paper at 25yrds. Is this a problem with the s&w .40 round? Neither of us know someone with another .40 to ask about it. We have a theory in mind that it could be the porting doing it. There is 2 holes on each side at 10 and 2 o'clock we where wondering if it could be throwing off the spin of the bullet as it leaves the barrel. Has anyone had experience with one of these with factory porting? And is it a gun problem or just nature of the beast with the .40 cal round due to it flat nose?
 
I have a M&P in .40 S&W. I don't have problems with groups out at 25 yds when I do my part. Try branching the pistol and see if y'all haven't developed a bit of a flinch with the sharpness of the .40 round and the muzzle blast that the porting can add.
 
We have benched it using sandbags and we are used to the recoil and muzzle blast, especially him and this isn't a bought the gun yesterday kinda thing hes had for close to a year. Pulling a few shots I'd agree it's the shoter but it's a very consistent problem
 
Sigmas were never the flagship product the company had hoped for, the compacts often just did not work. On the other hand I have shot many Sigmas and their 25 yard accuracy was as good as issue Glock pistols, perhaps yours has some unknown problem that S&W service can assist you with.
 
  1. Have you let someone else shoot it @ 25yds?
  2. Have you tried different ammo, and more specifically, different bullet weights?
  3. When you benched it, did you dry-fire first to make sure you were truly holding the gun steady? In my experience, handguns with stiff triggers (such as Sigmas) can move around in unpredictable ways when shot off sandbags, and may require adjustment to the shooter's trigger technique.
  4. How large of a target are you using, and have you tried a bigger one @ 25yds? You can extrapolate trends from lousy hits on a large target, but you learn nothing when you miss a smaller target completely.
  5. Do the bullets show any signs of keyholing- i.e. impacting sideways- at short to intermediate ranges?
Re: #5, if a bullet is reasonably well stabilized when it leaves the muzzle, it will become more stable rather than less stable as it travels farther. This is why benchrest rifles often shoot tighter MOA groups at 300+yds than at 100-200yds. OTOH if the bullet is not stabilizing properly, you should see signs of this at ranges under 25yds.

Another random idea is to try ignoring the white dots on the sights, or even coloring them in with dry-erase marker or taping over them with bits of black electrical tape. The white dots are meant for speed, not precision, which is why target pistols rarely have them.
 
It does seem to defy the laws of physics for a group of 2" at ten yards to be as wide as you describe at 25 yards.
Group sizes are relative to the distance.
It's kind of hard for a modern pistol to act like a blunderbuss.
 
The S&W Sigma (and similar, later models) have pretty heavy, ugly triggers. You'd be surprised how much difference that makes as the distance gets greater. Just sighting and holding on the target at the greater distances can be an issue. (On a local forum, a guy was complaining about hitting 12" high with a Glock 17L at 50 yards. I used the Brownells Sight Correction Calculator to show him that raising the front sight height (or lowering the point of aim) just 4/100ths of an inch would drop the point of impact 12".) It would be easy, with a crappy trigger, to make a MUCH bigger group at 25 yards. (Shooting at 50 yards is beyond my skills -- and my eyesight.)

The porting shouldn't be more of an issue at 25 yds than at 10 yds. Any negative effect should show up at closer distance, too.

You might want to go to the S&W forum and see if there are any tips for inexpensively improving the trigger -- or have a local gunsmith see if he can improve the trigger. Or just sell the thing.

S&W can also tune the trigger, and I think they're very reasonable -- maybe free -- but shipping it there is costly. I've read some surprisingly nice things about these guns, after S&W gunsmiths have waved their magic wands.
 
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I have one and though never sandbagged it can't find fault with it, some don't like the heavy trigger pull though. Being brought up shooting double action revolvers, double action, I have no issues with the trigger pull. Feeds anything, always locks the slide back, no worries.
 
without a ransom rest there's is really no wy to tell if you believe your are shooting it correctly. other than checking the muzzle for a dent or other damage, and checking the bore for any degradation on the latter end of the barrel and checking to make sure the barrel is locking in tightly with the slide. if all those things are good and your shooting it well, I would jump to say you need to start playing with ammos, try heavier.
 
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