S&W Sigma SW40VE jamming issues

[Dooligan]

So, I tried to find a fix, but couldn't.

My roommate just got a used SW40VE and he is having jamming issues.

Apparently, with a full mag, the gun has a tendency to jam. With half a mag or less it runs fine.

Is there a fix for this? He tried a bunch of different ammo with the same results, so I was wondering if it is a problem with the ramp? If this is a better question for the gunsmithing section?

Thanks!

[Shenaniguns]

Return the Sigma for a real M&P!

[Dooligan]

Cheap trade for cheap trade...not an option. He's gotta make do with what he has.

[Shenaniguns]

Please don't call it a M&P next time HAHA

[Dooligan]

Fine. I'll call it what I call every other M&P.

Edit: Whoops...thought all S&W autos were M&P. My mistake.

[Kestryll]

So does anyone have anything HELPFUL to add...?

[Briancnelson]

What kind of jam? FTF? FTE? Has he made any changes to the gun, like the "Sigma Trigger Job"? Does it look like the prior owner made any changes? Any unusual wear? Does the feed ramp look chewed up?

Little more information would help.

I'm a little doubtful its a feed ramp issue if it feeds well with half a magazine. You might look at the polymer guide rod, see if there's apparent damage to it or to the spring. Might be that the recoil spring is hinkey.
Most of the ones I've known to be jamomatics had the Sigma Trigger Job done on them. You should leave the trigger stock, IMO. Oh and also you should make sure you are installing the guide rod correctly. Some people put the base in the little cutout in front, it should go all the way down against the flat part. I've seen that bend the rod or cause the recoil spring to not work properly.

There's not a whole lot else that can go wrong on a Sigma, very simple pistols.

The ones I had were very reliable, before I sold them. Really the only thing negative about them was the stiff trigger, and you could get used to that pretty quickly.

That isn't to say I don't like my more expensive guns better, but they weren't jam o matics.

[Shenaniguns]

So does anyone have anything HELPFUL to add...?

Sorry Kestryl there isn't enough relevant info to help him and he listed the incorrect model.

[ojisan]

If the gun works fine with half a mag full or less, then the gun is not the problem, it is the magazine.
Try a couple differnt mags in it first, using quality ammo to remove as many variables as possible.

If a fully loaded mag has the rounds positioned nose down, then possibly there is a problem with the follower or maybe the spring is in backwards.

[Dooligan]

Sorry I don't know his gun in and out (and I have never owned an S&W auto), so I don't know ANY S&W autos in and out. If I worked at a gun store, maybe I would know everything, but alas....

The previous owner definately did not have a trigger job done, but IIRC, he bought it used too, so who knows what was done before him. It is always FTF, no instance of FTE to speak of yet.

Since he only has one mag right now, would it be better to by a factory mag or an aftermarket mag (if there is such a thing available for the Sigma) to test whether it is a mag malfunction?

I'll look for damage tonight. If there is, I will take pics and post them

Thanks

[Sturnovik]

If the gun works fine with half a mag full or less, then the gun is not the problem, it is the magazine.
Try a couple differnt mags in it first, using quality ammo to remove as many variables as possible.

If a fully loaded mag has the rounds positioned nose down, then possibly there is a problem with the follower or maybe the spring is in backwards.

+1.

[ojisan]

I have a SW40VE and some mags, of course, if you are local and want to test a bit.
I would definitly use a genuine S&W mag when testing...no point in bringing another possibly questionable mag into the situation.

[Briancnelson]

The mags are very hard to come by atm. I also question whether it is the magazines, if both of them have the same exact problem. Best way will be to find someone who has a Sigma and use theirs for a range trip, see if you get the same malfunction. If you do, then its not the magazines. You can do a few things to check your magazines however:

Check to see if the springs are noticeably weak by loading it with rounds and paying careful attention to how hard they are to get in. The springs on mine were pretty strong, it took a fair amount of effort to load a round. Then see if the follower sticks when you just play with it out of the gun (try loading it, then flicking the rounds out one at a time and seeing if there is any catching or hesitation in the next round moving up, to see if the follower is jamming and not pushing the rounds up). if it works with 6 in it but not 10, it may be the follower is catching near the bottom of the magazine.

If it's nice and stiff when you are loading it, and you aren't seeing jams on the follower, then it may not be the magazine, and I'd check the guide rod after field stripping it (I know someone who had similar problems after bending their polymer guide rod). If your ramp is chewed up, you might try polishing it.

Lastly, if none of those solve the problem, pull out the trigger group (lots of information on this on youtube, look up sigma trigger job, it's very easy) and see if the pigtail spring or the outer sear spring are removed. If so, you may need to replace them, and reinstall them (very simple, anyone with minor mechanical aptitude can do it). The removal of those springs somewhat lightens the trigger pull, but is also responsible for some Sigmas turning into jamomatics.

If none of that solves the problem, then you'll have to run it by a gunsmith and see if he can diagnose it.

[tonelar]

New recoil spring should fix plenty. If the tension of a full magazine is (dragging or) slowing the slide sufficiently, I can see a weak recoil spring being his culprit.

[BigfootHunter]

Also, instead of a new magazine might try replacing the magazine spring?