I have a CS9. When I lock the slide back and insert a full mag (or reload after emptying the gun), the slide lock will not drop when I pull back on the slide. I have to manually drop the slide lock and let it go forward. It only does this on mags with more than one round in it.. The gun was sent to S&W because the replacement guiderod I bought for it (S&W factory) was making it nearly impossible to get the slide stop out. They fixed that part, but now this. Any ideas? Also, if you try to drop the mag with any ammo in it and the slide locked back, the round gets hung up on the inside nub of the slide lock and it won't drop free. You gotta pull the mag out.

Is ur slide stop spring loaded detent free of rough marks?

Spring damage? Spring tension?

Field stripped.....install slide stop and ck for free movement.

Ref the mag....is the top round in the mag moving slightly fwd with friction from the under side of the slide or stripper rail? This is a common occurance with sw ninas.

Can't really see the slide stop spring.

Stop moves freely when empty. Lock it back with no mag and pull the slide and it works everytime.

I know when you chamber a round with a S&W, the next round down will usually move forward, causing the mag to not drop as free as it should, but in my case, there is no round chambered. I put a mag with rounds in there with slide locked back and it will not drop free. if there is only one round in the mag, I can pull the slide back and it will chamber as it should. Two or more rounds and it won't.

is there any copper tracks (markings) on your slide stop (inner portion) where the slug might be making contact?

what ammo?

No markings. Ammo is Gold Dot, but it's doing the same thing with snap caps.

I am gonna go play with with my CS9 and gold dot. See what happens.

could they have changed the slide stop when it was at SW?

or maybe the new guide rod is exerting extra pressure on the slide stop pin....

with my CS9 on slide lock, no mag....I retract the slide, the slide stop clicks down on its own.

same with a mag full of Gold Dots.

shoot it.....see if things change for the better or I send it back.

all guesses. sorry I cant diagnose without having the gun in front of me.

It's the same slide lock, but I remember he said he "fixed it" when it was in there. The gun came with the original nylon tipped guiderod. Being the anal guy that I am, I ordered a new factory steel tipped one. With that guiderod in, I needed to use a hammer and punch to pop the slidestop out for field stripping. I sent it back. He did something to the guiderod and the slide stop. I no longer needed to use a punch. But now this happens. And the only reason I discovered it (I haven't been to the range with it yet) is I was loading the gun to go out and for some reason I did it with the slide locked back first. I put the original nylon tipped one back in and no difference. I emailed S&W and am waiting on a response. I'm gonna shoot it Tuesday, but either way, it's going back. It's not supposed to do this.