So went to range today with the Shield .40. Shot about 50 rnds. Two times in a row the slide did not lock back after last rnd. It kept working correctly after. Ive been reading on line where it could be do to ammo or too strong of recoil spring and also spring in mags. Anyone with same issue on Shield?

Well not being able to see you shoot, I hesitate to say it could be a RSA issue. Are you able to control that snap on you .40 Shield?

Same thing with different magazines? DLB

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Almost all times in these posts, the operator figures out they somehow were placing their thumb on the slide lock, and in such a way as to depress the lock during recoil, so the slide would not lock back. If this is not the case, then you may have a defective mag follower, that is not raising high enough to hold the lock up. Check to see if all empty mags will hold the slide back when you manually rack the slide back. If so it is most likely option one. Not normally a spring issue, but could be a stuck/sticking follower. Clean the inside of the mag tubes and the followers, assemble with no oil. If during your next trip to the range, when you know your thumb is not causing the condition, and it happens again, start another thread. State in the thread that you know it wasn't caused by your thumb.

Bob

The follower in the magazine is what locks the slide back on the last round. It does this by pushing up on the little ledge on the inside of the slide lock lever (on the outside is the serrated part of the slide lock YOU activate).

If you're thumb is resting on the slide release while you're shooting the follower can not push it up and therefore it won't lock the slide back.

Easy enough, or so you would think...

I also had this issue but to a higher degree. My slide lock (when new) had to be pushed up and down to engage and or disengage the lock. The lock was for lack of a better term, Gritty/Sticky and wouldn’t move freely from general spring pressure. I ended up disassembling the trigger mechanism and polishing the inside (area between frame and locking bar) of the locking bar as well as lightly sanding the inside of the frame where the bar was grinding/sticking up on with some 1500 grit… Now the lock works flawlessly every time and is smooth as butter…. Enjoyed the armature gunsmithing adventure and learned a lot about the inner workings of my everyday carry as well. I also watched robkarrobs videos on the Apex kit for the shield and that to was a snap to install with outstanding results…

I would hope the slide lock would have been the first thing you checked. The spring pressure should keep the lever down, and it should only take a minimum of pressure to raise the lever. Check #1 is the lever itself functioning properly.

Bob