The first time I took her out she would lock back only every other mag. I figured my grip had some to do with it so I practiced dry firing with a grip that doesnt come even close to the slide release. But after taking her out again and after a couple hundred rounds she has gotten worse. She would not stay back, not once and I used new 10 round Sig Factory and used 15 Factory mags. This is my first Sig and even though she is beautiful I am very disappointed. I never had this problem with my uglier H&Ks. Any ideas?

the mag follower is what engages the slidestop I would cheack to see if there is any obstruction or better yet feild strip clean lube and reassemble.

I cleaned it very thoroughly the first time I took it out and it seemed to only get worse the second time.

Step 1)

ID those mags that fail to engage the slide catch

Step 2)

Disassemble those magazines and check how the springs are oriented.

Step 3)

Reverse the springs and reassemble the mags

Step 4)

Check mags and see if they now engage the slide catch


I had a NIB P226 that had a few (factory) mags that would not engage the slide catch. Turns out the spring was installed wrong and prevented the follower from going all the way up.

Quoted: Step 1) ID those mags that fail to engage the slide catch Step 2) Disassemble those magazines and check how the springs are oriented. Step 3) Reverse the springs and reassemble the mags Step 4) Check mags and see if they now engage the slide catch I had a NIB P226 that had a few (factory) mags that would not engage the slide catch. Turns out the spring was installed wrong and prevented the follower from going all the way up.

I'll try that. And the slide stays back when I cock it, but when fired it does not.

Probably the most common problem with SIGs.  A few ideas:

Make sure you’ve removed all the factory preservative that it was coated with.

Pistol should be clean and well-lubricated with a quality lubricant such as FP-10 or Breakfree.  As an experiment, try using a little extra lubricant on it and see what happens.  In particular, make sure the slide rails, the entire outside of the barrel (to include the top of the hood), and the recoil spring guide are extra well-coated.  Note though that this may result in getting some lubricant spray in your face when firing the pistol.

If you’re just using one type of round (esp. if it’s a standard velocity round), try something different (and preferably hotter).

If you’re using older 15 round mags, you may need to replace the mag springs (and maybe even the followers).  However, I’d think the 10 round mags would have new springs and followers and be OK.

+1 for making sure the mag springs aren’t backwards.

While very unlikely, I have seen females have the problem as a result of limp-wristing.  Try holding it very firmly with both hands and see what happens.  Be sure to grip the backstrap as high as possible.

When trying to figure out the problem, I suggest you just load one or two rounds in the mag to speed things up.  You don’t need to shoot an entire mag to see if it’ll go into slide lock on the last shot.

The new nitron finish seems to be very abrasive and needs to wear in a bit.  Hopefully that’s part of the problem.  Obviously at some point you don’t want to have to be doing some of the things listed above for your pistol to work.

Alternatively, there might actually be something wrong with the pistol.  If nothing else works, a phone call to SIG may be in order.

Good luck!  Lets us know if you ID the problem.

Quoted: Probably the most common problem with SIGs.  A few ideas: Make sure you’ve removed all the factory preservative that it was coated with.

I'll double check that; but I did clean it thoroughly before shooting it the first time

Pistol should be clean and well-lubricated with a quality lubricant such as FP-10 or Breakfree.  As an experiment, try using a little extra lubricant on it and see what happens.  In particular, make sure the slide rails, the entire outside of the barrel (to include the top of the hood), and the recoil spring guide are extra well-coated.  Note though that this may result in getting some lubricant spray in your face when firing the pistol.

I will drench it next time I take it out. I usually keep my weapons pretty lubed.

If you’re just using one type of round (esp. if it’s a standard velocity round), try something different (and preferably hotter).

That is probably the best idea; I will put some +P and +P+ through her.

If you’re using older 15 round mags, you may need to replace the mag springs (and maybe even the followers).  However, I’d think the 10 round mags would have new springs and followers and be OK.

I am hoping that the 15 rounders are not part of the case (I just got them on AR15)

+1 for making sure the mag springs aren’t backwards.

While very unlikely, I have seen females have the problem as a result of limp-wristing.  Try holding it very firmly with both hands and see what happens.  Be sure to grip the backstrap as high as possible.

My grip was so high that I thought that maybe I was bumping the slide release. So I now have my thumbs pointing down (rather then the 1911 style) I wont go into detail about all the FTE with my wife shooting it

When trying to figure out the problem, I suggest you just load one or two rounds in the mag to speed things up.  You don’t need to shoot an entire mag to see if it’ll go into slide lock on the last shot.

Luckly I was inteligent enough to do that.

The new nitron finish seems to be very abrasive and needs to wear in a bit.  Hopefully that’s part of the problem.  Obviously at some point you don’t want to have to be doing some of the things listed above for your pistol to work.

Alternatively, there might actually be something wrong with the pistol.  If nothing else works, a phone call to SIG may be in order.

I will take her out one more time put another couple hundred through her and if I still have problems then I will be calling Sig

Good luck!  Lets us know if you ID the problem.


Thank you 199 for your input.

Quoted: ...I am hoping that the 15 rounders are not part of the case (I just got them on AR15)...

I forgot to mention that stripping and cleaning your mags might also help.

FWIW, the older made in Germany/West Germany OEM mags had – IMHO – rather weak springs to begin with.  These springs also seem to take a set fairly quickly.

If this is what you’ve got, I’d recommend you replace those springs anyway – preferably with Wolfe + 10% springs (if available).

The newer Mecgar made in Italy OEM mags have much stronger springs.  I wouldn’t think those would cause any problems.

Note that the German made mags have witness holes along the back, the Italian made mags have the witness holes along the right side.

It doesn’t appear to me that the springs in the above two types of mags are interchangeable.

One more word on Sig cleaning and lubrication:

Sig pistols (at least the "Classic" ones) are considered "wet" guns; ie: they should be generously lubed...almost to the point that they are dripping with the stuff.

Sig pistols are made with extremely tight tolerances (they are so tight that you can take multiple pistols, completely disassemble them, mix-up all of their parts in a bucket, and re-assemble them with nary a problem). Because of the close tolerances, they need lube. I have spent multiple weeks at SigArms, and I have been told this by the guys that teach their armorer's courses.

Pay close attention to the rails on the frame and the "shoe" just forward of the magazine well (the flat metal part above the take-down lever). These areas need a nice amount of lubricant.

I had the same problem with one of my mags for my 200R. I took it apart and could tell the spring was bent. I just straightened in up and stretched it out a little, and it worked fine after that.

Don't worry, my CPO 226 has the same problem, and it ain't mag related, because it did it with every 226 mag I tried.

I'm going to take it out next time WELL lubed, and hope that it will loosen the thing up.  Just cause it was a CPO I guess really doesn't mean it was fired all that much.  Hopefully its just a break in issue, otherwise the things going back to sig.  No , I dont limp wrist the thing.  No, my grip is fine.  An no, I don't shoot weak ammo.  I shoot the same ammo through the 226 that I have put thousands of rounds through in a beretta 92, CZ P01, and P2000.  Federal American Eagle, and its plenty strong.  Ain't shooting +p ammo through this thing at the range just to lock back a damn slide.

Lubed or dry, the damn thing should lock back especially if it takes a trip back to Sig- I have absolutely no problem if its simply a break in issue, and will keep it and shoot the piss out of it.  I just don't get why Sig has not corrected this problem yet.  There OBVIOUSLY is an issue if this is happening to so many people.  I mean locking a slide back on a firearm ain't rocket science.  Its not like its a new concept that needs to be perfected.  If it goes back and they "fix" the problem and the gun gives me any issues regarding lock back with "standard" amounts of lube, I'll sell it and replace it with a USP 9 and chalk it up as a learning experience.

Why won't my slide lock back after last shot fired?

Quoted: Don't worry, my CPO 226 has the same problem, and it ain't mag related, because it did it with every 226 mag I tried. I'm going to take it out next time WELL lubed, and hope that it will loosen the thing up.  Just cause it was a CPO I guess really doesn't mean it was fired all that much.  Hopefully its just a break in issue, otherwise the things going back to sig.  No , I dont limp wrist the thing.  No, my grip is fine.  An no, I don't shoot weak ammo.  I shoot the same ammo through the 226 that I have put thousands of rounds through in a beretta 92, CZ P01, and P2000.  Federal American Eagle, and its plenty strong.  Ain't shooting +p ammo through this thing at the range just to lock back a damn slide. Lubed or dry, the damn thing should lock back especially if it takes a trip back to Sig- I have absolutely no problem if its simply a break in issue, and will keep it and shoot the piss out of it.  I just don't get why Sig has not corrected this problem yet.  There OBVIOUSLY is an issue if this is happening to so many people.  I mean locking a slide back on a firearm ain't rocket science.  Its not like its a new concept that needs to be perfected.  If it goes back and they "fix" the problem and the gun gives me any issues regarding lock back with "standard" amounts of lube, I'll sell it and replace it with a USP 9 and chalk it up as a learning experience.

Ditto, I am waiting to see if H&K comes out with a new pistol line, and if necessary I will buy a full size 9mm. And to think I sold my Compact 9 for this thing.

Quoted: I had a NIB P226 that had a few (factory) mags that would not engage the slide catch. Turns out the spring was installed wrong and prevented the follower from going all the way up.

Same thing happened to my first SIG, a 226-9-B, about 9K rounds ago.

+1 on the mag spring, I had one that did that...I guess this is more of a widespread problem. I figured someone just cleaned the mag and installed the spring incorrectly prior to my purchase.
I have a 226 and a 229, 15 mags (MecGar and W.Germany factory) for each and the slide locks back on all no probs.

has to be an after market mag SIGs don't break lol

5 out of 6 my mags are Sig (other is Meggar)

Two week old 226r Tactical won't lock back either. Fired 600 rounds and so far not any better. Will try another outing with her before calling Sig. Cheater gone.

Just took my P226R out again. This time I used +P for the last round to see if that would fix the failure to keep the slide back after the last round. And it did; after a few mags I went back to the regular ammo and the first mag stayed back. The next mag FTE, and then the next failed to keep the slide back. This sucks! Its a Sig; whats up with that? This will definately be the first and last Sig I buy, I'm going back to H&K

Now that you have convinced us how bad it is, how cheap will you sell it to me for?

Quoted: Now that you have convinced us how bad it is, how cheap will you sell it to me for?