Need help. Slide not locking back.

[cobra357]

Playing with my 4006TSW last night and noticed the slide not locking back with/without mag. Any ideas?

I tried to search for an answer but my skills there must be lacking.

 

[MichiganScott]

Pull the slide back and push the slide lock lever into place. It will not lock back without help by you or the magazine. I find it easier to leave the mag in place, pull the slide back, and then eject the mag.

 

[Deadctr]

To clarify a bit. The slide should lock back when there is an EMPTY mag present (whether at last round fired or manually pulled). Otherwise, you will need to manually lock it open.

 

[cobra357]

To clarify a bit. The slide should lock back when there is an EMPTY mag present (whether at last round fired or manually pulled). Otherwise, you will need to manually lock it open.

That's the thing on all my other 3rd Gens it locks without the mag but this one does not. Something is amiss.

 

[Arik]

That's the thing on all my other 3rd Gens it locks without the mag but this one does not. Something is amiss.

That's weird. I've never seen a semi auto lock the slide back without an empty mag. Not one no matter the manufacturer. The mag follower is what activates the slide lock

 

[Muss Muggins]

That's the thing on all my other 3rd Gens it locks without the mag but this one does not. Something is amiss.

I don't know of a single properly functioning semiautomatic handgun that the slide will lock back without an empty magazine or upward pressure on the slide stop lever . . .

 

[old&slow]

That's the thing on all my other 3rd Gens it locks without the mag but this one does not. Something is amiss.

?? The empty magazine is what activates the slide stop.

If the slide stop activates without an empty magazine , something is wrong with all your other autos.

 

[cobra357]

Sorry. Trying to do too many things too early in the morning.
I does not lock with an empty mag inserted.

 

[GaryS]

Sorry. Trying to do too many things too early in the morning.
I does not lock with an empty mag inserted.

Have you tried more than one mag?

 

[old&slow]

Sorry. Trying to do too many things too early in the morning.
I does not lock with an empty mag inserted.

Most of the time a problem with the magazine. The 'step' on the follower worn, or the follower not coming up far enough / completely. Weak magazine spring. etc..

Could be a problem with the slide stop,, defective ,, damaged,, sticking,, etc. But usually it's the mag..

 

[cobra357]

I do have two mags. Don't recall if I tried them both.

 

[Babalooie]

If you have a habit of using the slide release to close the slide while an empty mag is still in the gun, the follower "step" will prematurely wear.

Replace the follower and remove the empty mag before releasing the slide.

 

[Muss Muggins]

If you have a habit of using the slide release to close the slide while an empty mag is still in the gun, the follower "step" will prematurely wear.

Replace the follower and remove the empty mag before releasing the slide.

BS. That's comparable to saying that the mag springs prematurely wear if kept loaded.

 

[Babalooie]

BS. That's comparable to saying that the mag springs prematurely wear if kept loaded.

The metal slide rubbing against the plastic/nylon follower.......

 

[03Fatboy]

I think I would simply try a new mag spring. Do you have another magazine to try?

 

[cobra357]

Both mags feel like the springs are soft and followers don't look so great. Don't have a local supply so I'll have to order one most likely. Not in a rush as this is my only 40. Just hope it don't get lonely.

 

[Neumann]

I've had to replace a slide latch in a SIG, which was either worn or bent by a previous owner. It worked fine after the replacement. There are other things to check first, however.

The most common problem is a weak magazine spring or worn follower. For a short term fix, you can stretch the magazine spring a little to add tension. In doing so, you exceed the elastic limit of the spring, which tends to weaken it.

It's also easy to install the magazine spring incorrectly - either upside down or reversed front to back (or both). This will adversely affect feeding and slide lockback. Check online for instructions or exploded diagrams.

 

[Fastbolt]

If you're trying to lock the slide back with an empty gun, using an empty magazine, and it fails to lock back (without you pushing upward on the slide stop lever), typically there's a problem with ...

Damaged magazine follower
Damaged or worn magazine spring
Dirty magazine
Damaged slide stop
Damaged side plate

I've also seen a couple guys reassemble their 4006TSW magazines with the followers installed backwards. This located the little shelf on the follower (that engages the slide stop lever) on the wrong side of the magazine, where it couldn't be engaged by the slide stop lever tab.

If it were me, I'd inspect the magazines to make sure the followers are installed correctly.
View of .40 follower from right side:


View of .40 follower from bottom, with left side of follower facing bottom of pic:


I'd take the EMPTY pistol and EMPTY magazines (as many mags as you have), and briskly retract the slides on the empty mags to see if the followers lift the slide stop levers and lock the slide back. If they don't, it's possible you have older/worn springs that need replacing.

S&W recommends its armorers replace recoil & mag springs either every 5,000 rounds fired, or every 5 years of normal service use, whichever occurs first.

I'd check the slide stop lever assembly to make sure the plunger is under tension, and freely moves in & out if you push against it.

I'd check to make sure the side plate is fixed in position. (Not uncommon for someone to unintentionally tweak and damage a side plate when removing/installing factory grips, if the top front/left corner of the grip snags under the side plate and exerts excessive pressure upward against it when installing & positioning factory grips.)

BTW, a locked back slide normally can be released - with or without a magazine in the gun - by simply pulling back on the slide and letting the spring tension of the slide stop lever's plunger push the lever downward, out of the slide's "stop notch".

One of the normal bench checks an armorer does is to take an empty pistol, and its empty magazines, and briskly run the slide to the rear, letting it go, with each magazine. If the slide isn't captured by the follower/slide stop, the mag spring is probably getting too weak. The "next" symptom is usually the slide failing to lock back in live-fire, and/or last round feeding failures.

A weakening recoil spring can start to let the gun batter itself, which is how slides and frames can get cracked/damaged.