Shield hangs out of battery, think I found the issue...

[rsrocket1]

Nice writeup redwing. You'll notice that one of the seven lubrication points in the manual includes the top of the trigger bar where it contacts the striker block. That little extra bit of resistance could make the difference between hanging up and allowing the slide to return to battery.

 

[redwing57]

Ok, one more comment for those who may read this far down! One other thing that's happening in that last 1/8" of travel into battery involves the chambering round. If you look closely where the barrel meets the breech face, you'll see because the barrel rocks, that the round is sliding up the breech face, while under the edge of the spent-casing extractor, and may have some pressure there. Also, the two lugs at the top of the barrel (spanning the open spot to visually see a round is chambered) seem to also contact the breech face and ride up just a bit.

This is a little controversial, but I've taken a very lightly oiled q-tip and rubbed over the breech face, extractor, and the barrel lugs. It's a really small amount, you can't even tell it's there. But it seems like anything I can do to reduce friction everywhere will help. Be very careful not to get any oil in the firing pin hole. It will gunk up and give light strikes if you do.

Finally, I'm using Weapon Shield lubes, since they are claimed to help smooth metal surfaces that are under high contact pressure.

 

[Stratajema]

...This is a little controversial, but I've taken a very lightly oiled q-tip and rubbed over the breech face, extractor, and the barrel lugs. It's a really small amount, you can't even tell it's there. But it seems like anything I can do to reduce friction everywhere will help. ...

Yes, reduce friction using oil or grease when the gun is not at the range and will be used for self-defense. However, the best way to reduce friction is to allow the metal parts to mesh and wear together without oil/grease, for a limited time, during firing at the range. For those people who do not fire their guns (and they are actually in the majority, e.g. city dwellers), cycling the slide by hand without oil or grease is not enough to allow the metal parts to mesh together. Rather, it is the unique stresses during the firing of the gun that best allow the meshing of surfaces. (E.g. see this slow motion video of a gun being fired: https://www.youtube.com/watch?v=7Fr5ccyriJI )

The issue of the Shield hanging out of battery has been discussed since the gun was first introduced. It is principally caused by the strong upward pressure of the top round in a fully loaded or nearly fully loaded magazine, hitting against the slide's loading rail. Other combinations of causes include the pressure of the extractor against the chambered round's casing, the trigger disconnector riding the bump in the slide, and the barrel-to-slide lock up points of contact.

Inevitably, people always fail to discuss that it is the job of the recoil spring to overcome all of the above mentioned forces of resistance. However, people who replaced their recoil spring reported that it did not eliminate the problem. The solutions discussed are to apply a very small amount of grease (not oil) on the disconnector bump area on the slide, to apply a light coating of oil (never use grease!!) to the slide's loading rail, and to reduce rounds in the magazine by -1 from the maximum (e.g. 6 rounds in a 7 round magazine).

In my Shield, the principal cause of hanging out of battery is a fully loaded 7 round magazine... but not a fully loaded 8 round magazine. Rather than carry -1 in the 7 round magazine, I am going to try the MagGuts product and only load 7 rounds in it.

 

[Rastoff]

Nice writeup redwing. You'll notice that one of the seven lubrication points in the manual includes the top of the trigger bar where it contacts the striker block. That little extra bit of resistance could make the difference between hanging up and allowing the slide to return to battery.

No, this can't be part of this problem. The trigger bar only contacts the striker block when the trigger is held back.

 

[wyomick]

My ported 9 does an OOB thing in the middle of a mag occassionally, but more so with a SS RSA upgrade I have. When I put the OEM RSA back in, it does it very seldom - so, I think that has something to do with it; i.e., the spring and the slide weight (or in my case, lighter weight; ergo less momentum going forward to close due to the porting, especially on a slightly imperfect round (bullet seat, case dimension, etc - factory ammo; not reloads). Check the under side of the slide top and see if there are little drill indentations where they milled out slight bits of material to "balance" the slide, or get the weight "just right". I think S&W knows they've got a problem or issue in this area. As an engineer also, there's my two-cents worth, and thanks for the bump theory. I'll give it a bit of a polish just for the hell of it.