Hi all. Just wanted to run by before contacting the S&W. after 1400 brake-in period i started to notice that slide may not stay open after last round. Not happening to often, but enough to notice. I'm wondering if it's ammo, mag or the Shield itself. Ammo used is Aguila 124 gr +P.

oh, one more problem, one of the magazines is really hard to lock in when it's fully loaded and the slide is in forward position. When the slide is opened - it makes no diffeence - the mag goes in very easy and locks in. Now i'm wondering if both problems are related.

Thank you in advance.

I have both the 40 and 9mm. Both of them are easier to load the mag when the slide is open. So i'm pretty sure that isn't your problem.

Any chance you could be hitting the mag release when shooting? Thats a very common issue on Glock's. The other thing that comes to mind is to try different ammo. I have had issues with Aguila 124gr standard ammo. The stuff will shoot fine in my glock but chokes my 1911. Assuming the +P ammo is like the standard stuff then there is a crimp ring around the bullet little ways down on the case. There is always the possibility that could be causing the issue. The first thing I would do is check my grip try different ammo go from there.

I had that issue with a 1911 once and turned out to be the magazine, have you tried a new magazine to see if you have the same problem? I think it was the magazine follower that has a notch that pushes up on the slide stop lever bar internally to lock back the slide. It's very possible that either part may have worn down but most likely the notch on the magazine follower. You might want to check both parts to see if the magazine follower is pushing up on the slide stop lever. I'll search the web for a diagram or something that might help you. Also, the magazine spring may have gotten a little weak and may not be pushing up hard enough on the slide stop lever bar to engage it. Let me know what you find to be the problem.

Here a picture of both parts working together.

Attached Images

ImageUploadedByTapatalk HD1355996771.692790.jpg (28.2 KB, 501 views)

if you are not afraid of a little amature gunsmithing, here's what i would try;

see the little tab on the slide stop? that tab is picked up by the follower when the mag is empty and engages the slide stop. bend that down a bit, maybe a mm or two and see if that solves your problem.

__________________
NRA life member

Typically this is caused by the shooter "thumbing" the slide lock, so before doing anything else try shooting it left handed. With a pistol that doesn't feature an ambi slide lock/release shooting left handed is one method that guarantees that the slide lock isn't being thumbed.

If you are thumbing the slide lock a bit of attention to your grip during practice can provide a solution, however it can be a bit of a challenge to retrain yourself so don't expect an instant "cure".

The second possible cause is weak magazine springs and this is much less likely than the previous cause. I rather doubt that 1500 rounds would do it but it can happen and the fix is new magazine springs. BTW, new springs will make it MORE difficult to install a full magazine with a closed slide but that's the price you pay for having stiff new springs to lock the slide back.

PS; I would NOT attempt any kitchen table gunsmithing on the slide lock. Quite often they types of parts are case hardened and will snap if you try re-bending them. In addition there may be some aspects of the design you aren't aware of or don't see and you'll do nothing but create more problems. If you have a problem with your slide lock not working properly then use your warranty and send your pistol in for repair.

This is what of one of my mags does. VERY hard to install it, when it's full. Just taping hard on the bottom of the mad does not do it. i have to force it in until i hear a lock click. I'm wondering if that's he mag that causing problem not opening the slide on the last round. Will check this mag with my current ammo and theother mags with different ammo.
Edit. I swapped the springs between two magazines - the one that was a "suspest" still close to impossible to lock in. I'm sending it in for the replacement.

Everyone, thanks you very much for your inputs.


**********************************************
Oh, one more question please. How do you take care of the mags? do you clean them? how oftern? any oil on the spring?

My problem is to load when slide is closed. On opened slide nothing's holding/pushing on rounds - mag goes w.o any effords

with the slide closed and in battery, the magazine (if fully loaded) is going to be much harder to engage. Youre just going to have to live with it! Thats the sacrifice you make for a single stack that can hold 7-8 in one magazine.

I have another 7 rd and 8 rd mags, those are locking in with firm, but manageable pressure/tap. The other 7rd is impossible to engage by one motion; I need to force it to click. When I disassembled two 7rd mags - they have different springs. The one that very hard to engage has one more coil and slightly bended. I think it's either defect or 8rd mag spring got into 7 rd one. (Silly me - I have an 8rder to disassemble and see that is going on)

BBS1 is correct. If the magazine is fully loaded, the mag spring almost fully compressed. When you push the mag into the mag well with the slide closed, the top cartridge is further pushed down by the slide ram. Since the mag spring was almost fully compressed, this additional pushing down puts additional pressure on the mag spring and makes it harder to seat the magazine. When the slide is open, there is no additional pressure on the top cartridge, as the slide ram does not contact the cartridge. With fewer cartridges loaded into the mag, it is easier to insert the mag when the slide is closed.

There can be many reasons the slide does not lock open upon firing the last cartridge. The mag follower may be sticking and may not always popping fully up to lock the slide. Clean the follower and the inside of the mags. Do not oil.

Check the operation of the slide lock. It should be held down with the spring pressure. Check the operation to make sure it moves freely up and down. If sticking check for a bent lock or debris causing it to stick.

Last is the possibility of your thumb occasionally bumping the slide lock.


Bob

Bob, and others, thanks for the suggestions.

Today i used 250 rounds of Winchester 124 gr NATO ammo and the slide functioned correctly every time. So i think it was the Aguila ammo causing the problem. What i did, i put one NATO round firt into each mag, before loading the rest of mag with Aguila - after 150 additional rounds of Aguila i did not have "slide does not stay openned" problem.

The plastic followers were OK, but i cleaned all my magazines today.

Thanks again.

Just another hint. Number your Mag's. That way it is easy to spot a bad one. I'm glad your problem seems to be fixed. I look at magazines as disposable, they wear out just like recoil springs. I have a couple boxes of old mags. I use them for spare parts.